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Choices & Guidelines

Details: Last Updated on Tuesday, 10 March 2015

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Credit: css.org/CH2M HILL Great streets and great places look beyond the lanes carrying vehicular traffic to the pedestrian realm and adjacent land uses.

The image at right depicts the symbiotic relationship between motor vehicles, buses, MetroLink, bicyclists, and pedestrians that is necessary to create great streets.

We must recognize the symbiotic relationship that is necessary for all of these modes to flourish (not simply coexist) in one common environment.

As Allan Jacobs notes: "It's no big mystery. The best streets are comfortable to walk along with leisure and safety. They are streets for both pedestrians and drivers."

In designing great streets, capacity considerations will influence how much space should be allocated to vehicular traffic, transit, bicyclists, and pedestrians.

Capacity is a basic measure of the quantity of traffic a road can carry, or more specifically, the maximum sustainable rate at which pedestrians, bicycles or vehicles can be expected to travel across a defined point or segment during a period of time, typically expressed in vehicles per hour or pedestrians per hour.

Measuring and evaluating capacity can be a complex process, particularly for arterial streets with varying conditions and a lack of uniformity between segments. Street capacity is affected by many other design considerations, such as mobility and access. Increasing the number of access points along an arterial, for example, can severely limit capacity while increasing vehicular capacity can negatively impact the mobility of pedestrians. These concepts must all be carefully balanced, for all modes, to ensure great and safe streets.

Creating great streets begins with a solid understanding of the type of place you hope to create. The appropriate role of capacity for a given roadway is determined by:

The degree to which various modes are present
Abutting land uses
The role of the arterial within the context of the network

A common mistake municipalities make is widening roadways to enhance capacity and improve the flow of vehicular traffic, without considering all its effects. Roadway widening may be appropriate along some mobility-priority corridors. However, for corridors with a significant pedestrian presence, commercial, mixed-use, or residential development, and/or widespread transit use, widening streets to increase capacity is not the preferred solution. Widening streets detracts from the pedestrian experience, jeopardizes pedestrian safety, can displace or limit development, and may discourage transit use.

Who says we need more lanes When determining the appropriate number of vehicular travel lanes for a given corridor, it is important to consider the effects of such widening on pedestrians and adjacent land uses. The Florida Department of Transportation has developed several tables that can be useful for guiding capacity choices. The tables use a set of default values to approximate the amount of traffic a facility can carry based on the number of lanes, median type, number of traffic signals, and desired level of service.

Credit: CH2M HILL

These tables were designed for general planning purposes and are most useful in assessing the overall capacity needs of a facility, as opposed to specific LOS measures such as delay or average travel speed. See the Florida LOS table for more details. Transit can be an ideal way to add capacity to an arterial street system without widening the street itself (although some transit solutions might require widening the street, too).

Credit: CH2M HILL

Bus service can reduce the number of single-occupancy passenger cars on the street, resulting in better vehicular operations overall. Dedicated bus lanes and/or bus rapid transit should be considered in arterial corridors for long-range person movement capacity.

Credit: CH2M HILL

Transit is especially effective in areas with high density land uses that can produce stable and consistent ridership. Arterial corridors with heavy through-traffic should also consider placing a higher priority on bus lanes.

In light of the expanding bus and light rail systems, St. Louis should begin prioritizing transit along the region's arterials to increase capacity and mobility for all modes. It is important to point out, however, that bus lanes and other transit capacity measures are not without their challenges. Provision of these measures, particularly at intersections, must be carefully implemented to insure that they do not negatively impact the efficiency or safety of the overall intersection. See the Intersections section of this guide for more details.

Primary characteristics affecting capacity for residential place types include:

Significant pedestrian and bicycle presence; and
Transit presence

Depending on the target speed established for these thoroughfares, a variety of volumes can be serviced at several different levels. The tables below offer some general capacity thresholds, and can serve as an effective guide when considering the appropriate number of lanes to provide for a given street.

Credit: CH2M HILL

Design elements, such as narrower thoroughfares with street frontage, on-street parking and decorative signing can help create an environment more supportive of lower speeds by providing clues to drivers that they have entered a residential area and left the higher-speed environment. Intersection and pavement design can also help create a change in environment.

These places are teeming with pedestrian activity, and should therefore provide environments that are safe, efficient, and appealing for pedestrian travel. To do so, planners, designers, and local leaders should focus on the following pedestrian measures:

Provide sidewalks that are continuous and wide enough to provide the desired types of pedestrian services
Maximize the amount of lateral/horizontal separation between pedestrians and motorized traffic
Keep motorized speeds on the street as low as practicable
Provide frequent, reliable, and easily accessible bus service

Commuting to work or riding to school via bicycle is an increasingly popular mode of transportation. Such travel should be encouraged; it is environmentally responsible, reduces vehicular congestion, and is economically inexpensive for users. Bicycle trips begin at the residential neighborhood level, so it is important that these thoroughfares prioritize bicycling. The following measures can be taken to enhance bicycle travel in these civic and educational corridors:

Maximize the width of the outside travel lane and provide bike lane striping that is clear and visible, as shown at right. In areas where transit lanes are provided for buses, bike lanes can be well accommodated due to the lower volume experienced in those lanes.
Route trucks and heavy vehicles to other truck designated routes to minimize conflicts with bicyclists.
Keep motorized speeds on the street as low as practicable.
When drainage grates are required, make sure they are visible and "bicycle friendly."

Residents who choose transit improve regional capacity. These corridors are typically not major transit routes. The residents surrounding them, however, are ideal candidates for transit use as commuting options to work and school. To encourage such a choice, it is important to provide efficient and attractive connections to the transit system from these areas. Every resident that chooses to utilize the transit network is one less single occupant vehicle (SOV) on the road, thus improving the overall capacity of our regional network. The pedestrian and bicycle considerations described above are part of this provision because they facilitate efficient movement of local residents to transit connections. Additionally, these corridors should consider creative ways to encourage transit use. Way-finding signs that guide pedestrians to nearby transit connections are one such measure.

When transit routes do exist on residential thoroughfares, prioritizing this mode is essential. A variety of measures are available to do so:

Transit-only lanes. Traditionally, buses use the general vehicular travel lanes. Pull-off lanes, or pull-outs, at bus stops, can make it difficult for buses to reenter the stream of traffic and decrease the efficiency of transit use.

Transit-only lanes can help place a higher priority on buses and other transit service. These lanes provide dedicated space on the street for buses (and sometimes bicyclists or high-occupancy vehicles) and can help make transit a more efficient, viable, and attractive choice.

Transit-only lanes can be located on the outside of the travel way (near the shoulder) or on the inside of the travel way (in the median). Transit-only lanes may be in use throughout the day, or during peak periods only. Peak period prioritization is especially useful in areas with an extremely heavy peak period. The image at right shows an example of rush hour transit lanes that also serve bicyclists and high-occupancy vehicles (HOVs). An article from the Federal Transit Administration provides more information about Bus Lanes.

The degree to which transit lanes are appropriate is influenced by the following considerations:

Transit lanes occupy space that would otherwise be allocated to either vehicular traffic, the pedestrian realm, or front yards of local residential parcels.

Ridership levels must be high to achieve the types of capacity benefits that are possible with transit lanes. Low ridership makes transit lanes a less viable alternative.

Transit lanes require special planning and design at intersections. Care must be taken to manage the conflict between transit-only lanes and right-turning vehicles, which essentially requires a lane transition. These transitions must ensure that all users are able to safely and efficiently execute turning maneuvers. Pavement striping, clear signing, and taper lengths are important elements in effectively managing these transitions.

Transit bypass lanes, or "queue jumpers" are used to prioritize buses at intersections, allowing them to bypass congested queues forming in the vehicular travel lanes. Roadway designers should be aware of the potential conflict between transit bypass lanes and right-turning vehicles at intersections.

Appropriate location of bus stops (mid-block, nearside, or farside). The most appropriate location typically depends on site-specific characteristics. The tables at right and below describe the advantages and disadvantages of nearside, farside, and midblock bus stop locations.

Bus stop spacing is also important in prioritizing transit. The Federal Transit Administration article Stops, Spacing, Location, and Design, provides additional information on appropriate spacing and location considerations, with a focus on bus rapid transit (BRT).

Traffic Signal Priority is another way to prioritize transit along the thoroughfare. Here again, traffic signals are less common along residential thoroughfares. Where they do exist or are needed, though, special treatments and traffic signal technologies are available to detect and prioritize transit vehicles at signalized intersections. See the Federal Transit Administration's article on Signal Priority for more information.

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Public utilities are a frequently overlooked element of arterial street design, despite the significant implications their placement, maintenance, and design have on roadway functionality and cost. Both underground and overhead utilities occupy a significant space within the right-of-way. See the attached PDF document for a diagram of utilities.

Utilities which are commonly overhead:

Telephone
Cable television
Overhead lighting
Electricity

Utilities which are typically underground:

Water
Natural gas
Irrigation (sprinkler systems
Sanitary sewer
Storm sewer

The poles used to support overhead utilities can present a roadside safety risk in some corridors. Specifically, 10 percent of all fatal, fixed-object crashes are a result of motor vehicle collisions with utility poles supporting overhead utility lines. If utilities must be overhead, it is imperative that the poles and cabinets are located in the areas where they are least likely to be struck by an errant vehicle. AASHTO’s Roadside Design Guide offers several design considerations for maximizing safety when roadside overhead utilities are present.

Locate power and telephone lines underground, whenever possible. Burying these lines can be costly, especially in retrofit situations but the improvement in safety, appearance, and mobility for pedestrians is worth it.
Maximize the lateral distance between the vehicular travel way and utility poles. AASHTO recommends a minimum of 18 inches between the back of the curb and the roadway. The resulting tradeoff is that the utilities are then closer to building frontages.
Reduce the number of utility poles along the street. Maximize the spacing between utility poles and whenever possible, combine multiple utilities on a single pole (e.g. combine overhead lighting with a traffic signal and perhaps even a power line).
Use a breakaway pole design. This will minimize the impact and severity of collisions.
Credit: CH2M HILL

Use traffic barriers to shield poles. While barrier curbs lose effectiveness at speeds over 30 mph, low-profile barriers (as shown at right) can be quite effective for higher speed arterials (up to 45 mph).
Preserve pedestrian walkway. Overhead utilities significantly affect the character of the streetscape. In addition to being unsightly, above ground utility poles are often located along or even in the middle of the sidewalk, encroaching on the pedestrian walkway. The clear pedestrian walkway should be a minimum of five feet wide, even when poles are present. In downtown areas sidewalks should be wider to accommodate high volumes of pedestrian traffic and pedestrians using mobility aids.
Consider maintenance of utilities in the planning process. Utility maintenance (overhead or underground) should be considered when locating utilities and other roadside elements such as trees, street furniture, traffic signs, and drainage inlets that could potentially impede or prevent access.
Coordinate early and often. Utility coordination is an essential component of the planning and design of great streets. Most streets have a number of utilities, each of which may be owned and managed by a different agency. Frequent and early coordination with these agencies can save time and money, especially when service lines are being upgraded or relocated. Coordination between roadway planners and utility agencies can improve design and lower the costs associated with roadway construction or improvements. The agency responsible should understand utility plans for the corridor and provide the appropriate utility companies with street design plans early in the process to solicit comments. Close coordination can also minimize impacts associated with construction, particularly for adjacent property owners.
Credit: CH2M HILL

Locate utilities before making improvements to an existing roadway. A thorough subsurface utility investigation should be performed before beginning work on retrofit projects to avoid discovering unexpected utility lines, and the associated costs and setbacks.

Existing plans or “as builts” can be used in combination with detection technologies such as ground penetrating radar to identify unrecorded underground utility lines along a corridor. A relatively small investment of time and money early in the planning stage can help minimize unanticipated costs during construction.
Improve the aesthetics of utilities through design, signage, lighting, and seasonal decorations. There are a variety of simple, innovative ways to transform utility hardware into attractive streetscape enhancements. For example, ordinary traffic signal cabinets can be decorated with colorful, artistic murals linking the street to the surrounding land uses, as shown in the images below. Other improvements to utility infrastructure can involve partnerships with local businesses and residents to provide and maintain amenities, such as flowers and plants, lights and decorations. Involvement by citizens and local businesses can reduce costs, enhance community buy-in, and build mutual interest in creating and maintaining great streets.

Credit: CH2M HILL

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Although most transportation research, published articles, and popular discussion focus on the movement of motor vehicles through roads and intersections, cars actually sit in parking spaces 95 percent of the time. In many urbanized areas, parking assumes 20-40 percent of the land surface area.

The design and location of parking is one of the most important elements of great streets. The quantity, location, management, cost, and design of parking depend heavily on the adjacent land use the parking is serving. For example, parking design in downtown areas is very different than parking at a suburban office complex. Still, there are several parking principles that permeate all land uses.

Ensure on-street parking: On-street parking is the most valuable type of parking for several reasons:
- It creates a physical and psychological buffer between pedestrians on the sidewalk and moving traffic.
- It presents the best access to the front door of retail, residential, and commercial destinations.
- It limits the need for off-street parking facilities. Off-site parking facilities use valuable land, require additional curb cuts through the pedestrian realm for access, and present challenges to creating good urban design. Additionally, in urban areas, off-street parking facilities can be extremely expensive.
- On a per space basis, on-street parking takes up less land area than other forms of parking because the ramps, driveways, and aisles needed in parking lots and structures are absorbed by travel lanes themselves.
Place parking behind buildings: Fronting streets with buildings (as opposed to parking) creates a more interesting, pedestrian-friendly environment. Locating parking behind buildings also allows driveways/access points to be placed on lower volume side streets, presumably with fewer pedestrians. Placing driveways (including those to parking lots) on side streets creates a more continuous pedestrian frontage, reduces the potential for pedestrian-motor vehicle conflicts, and eliminates mid-block left hand turning movements on the higher volume street - a leading cause of mid-block congestion.
Encourage shared parking: Peak parking demand for adjacent land uses often occurs at different times of the day. For example, a bank and a neighboring movie theater could feasibly share spaces as their parking demand peaks at different times. Although such arrangements are more common in mixed used districts, shared parking can be implemented in all place types. Shared parking decreases the need for off-street parking spaces and lots, which imparts many of the benefits mentioned above. See the Urban Land Institute’s Shared Parking (Smith. Shared Parking, Second Edition. ULI and the International Council of Shopping Centers. 2005) for more information about shared parking.
Source: ADAAG
Provide handicapped parking: Federal law requires that handicapped parking be provided in all designated parking areas. The Americans with Disabilities Act (ADA) sets guidelines for handicapped parking requirements for all new construction. The minimum number of required handicapped spaces is based on the total number of spaces in the parking facility, as outlined in the figure at right.

The location of these spaces is also regulated, as explained below in the ADA Accessibility Guidelines:

“Accessible parking spaces serving a particular building shall be located on the shortest route of travel from adjacent parking to an accessible entrance” (ADAAG 4.6.2).

Although there are established national standards, individual municipalities often set their own standards for handicapped parking. A 1990 study of retail shopping centers found that the number of handicap spaces in commercial areas varied between 0.7% and 2.0% of the total parking supply (Weant and Levineson. Parking Spaces. McGraw Hill. 1999).
Include bicycle parking: Although automobiles typically come to mind when parking is mentioned, great streets have provisions for all modes, including adequate and secure bicycle parking. There are no national standards for bicycle parking, and local requirements vary widely. One of the most convenient methods for establishing appropriate bike parking design is to view the ordinances of municipalities with high bike mode shares. The city of Madison, Wisconsin, for example, provides excellent guidelines on the appropriate quantity, location, and design of bike parking. The city of Portland, Oregon also has an excellent web page with guidelines for installing bicycle parking.
Minimize supply: Parking is often oversupplied, which creates a number of design challenges. A 2003 study of 42 parking lots during the holiday season found that the average occupancy was less than half (Gould. “Parking: When Less is More.” Transportation Planning, Vol.28, No.1. Transportation Planning Division, APA. Winter 2003).
Source: City of Seattle
Retail shopping centers with massive parking facilities that are rarely (if ever) full are a common sight in most communities. Parking is oversupplied because the minimum parking requirements for residential and commercial development is often set at the annual maximum expected demand, leaving excess parking for much of the year.
Ensure delivery parking: Delivery parking must be provided in most, if not all, place types, but is particularly important in areas with a high concentration of retail shops and restaurants. Alleys are ideal locations for temporary truck parking, allowing back door delivery access away from customer parking and entrances. When alley use is not feasible, special loading zones can be designated. The image at right is an example of signage used in a loading/unloading zone.

Parking in Residential Neighborhoods:

Provide Alley Parking: Including alleys in residential neighborhoods can have a number of benefits, such as eliminating the need for driveways in the front of houses. Reducing the number of driveways in a neighborhood creates pedestrian continuity and allows for additional on-street parking where the curb-cut used to exist. (Providing off-street parking typically produces a minimal net gain of parking when on-street curb spaces are factored in.)
Garage Door Restrictions: In areas where alleys are not feasible, restrictions on garage doors should be considered. Many homes in residential neighborhoods have garage doors that dominate the front of the house. These garage doors are unsightly and create an increasingly automobile-dominated environment by suggesting that the house should be accessed by car. Possible restrictions include:
- Limiting the number of garage doors facing the street (e.g. the City of Carmel, CA set a one garage door limit)
- Limiting the percentage of the building façade covered by garage doors (e.g. the City of Portland, OR set a 50 percent limit)
- Requiring that driveways be as narrow as possible and shared whenever feasible, as the City of Olympia has done)
- Requiring garage doors to be placed on the side of the house. The front of these garages can be designed to look like livable spaces, which can help create a more interesting, inviting pedestrian environment.

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Source: FHWA An intersection is defined as the area where two or more roadways join or cross, but also includes elements of the functional area, such as intersection approaches, medians, sidewalks, bike lanes, and other roadside features.

The image at right highlights the physical and functional areas of an intersection. Intersections on great streets must serve all modes of travel.

Automobiles, transit vehicles, pedestrians, and bicyclists should all be given adequate time, space, and directional cues to safely proceed through intersections and continue traveling along the arterial. Balancing the needs of all users at multimodal intersections, while maximizing substantive safety is a complex and important challenge.

Source: FHWA

Intersections are points of conflict where modes of travel converge, as illustrated in the image at right.
Intersections should be carefully designed to include and prioritize the most appropriate place-specific design elements.
Intersecting roadways should cross at an angle of at least 75 degrees, ideally 90 degrees. When the angle of intersection is less than 60 degrees special design treatments may be needed to ensure a reasonable level of safety.
At intersections, medians can be used to provide separation between opposing traffic, channelization for turn lanes, and refuge for pedestrians.
Medians with landscaping and tree plantings can also be used to improve intersection (or roadway) aesthetics, although care should be taken not to affect driver or pedestrian visibility and sight distance.

Credit: FHWA

Movement through intersections is controlled using yield signs, stop signs, roundabouts, and traffic signals. The appropriate type of control for a given intersection depends on the place type and the amount of pedestrian and vehicular traffic.

The MUTCD provides guidance for selecting the appropriate type of control for various intersection conditions (see the following links for general information and specifics about signal warrants).

Different traffic control devices impose varying degrees of delay on pedestrians and vehicles passing through the intersection. The overall efficiency and capacity of a roadway is limited by the delay experienced at its intersections.

Some agencies and municipalities continue widening intersections by adding exclusive, dual, or even triple turn lanes in an effort to minimize delay along the arterial. While these improvements do increase an intersection's vehicular capacity, they also render the intersection more difficult for other modes of travel (especially pedestrians) to navigate. Because turn lane additions are typically retrofit projects they can significantly impact surrounding residences, businesses, and land parcels.

Designing intersections for great streets requires balancing competing needs, interests, and values, and responding to the unique circumstances of each street. Planners, designers, policy makers, and local stakeholders should collaborate to develop a community vision which can be used to guide the design and construction of intersections and roadway improvements.

Characteristics that influence intersection design for residential thoroughfares:

Significant pedestrian presence
Lower speeds desired
Single land use (residential), smaller parcel sizes
Quality of life, pedestrian convenience, and safety are all important drivers

Residential thoroughfares have high volumes of pedestrian activity. Providing the appropriate pedestrian facilities is vitally important for these thoroughfares. Roadway and intersection design should reflect this need for a safe, attractive, and comfortable pedestrian environment.

AASHTO's Guide for the Planning, Design, and Operation of Pedestrian Facilities offers the following as characteristics of good intersection design:

Clarity - Motorized traffic should be alerted to the presence of pedestrians; pedestrians should be able to easily identify crossing locations; both goals can be achieved using appropriate sign placement and design. Noticeable textures and colors can also be used to emphasize crosswalks for pedestrians and drivers approaching the intersection.
Predictability - Place pedestrian crossings in expected or predictable locations. In unexpected locations, use clear and visible signing, flashing lights, or beacons to alert drivers and pedestrians of the crossing.
Visibility - Providing adequate sight distance and appropriate lighting can improve visibility for both pedestrians and motorists. The sight distance required at an intersection is based on the design speed of the facility and constrained by various objects along the roadway (e.g. bus stop shelters, street furniture, utilities, building corners) as well as the street's vertical curvature. Although most mixed-use streets have relatively low design speeds, roadway planners and engineers should consider selecting sight distances for higher speeds to further increase visibility.
Short Wait - Minimize the time pedestrians spend waiting to cross an intersection. Consider special peak hour signal timing to meet the high pedestrian demand during these time periods.
Sufficient Crossing Time - Signals should be programmed to ensure that all users, including the elderly and individuals with disabilities, have adequate time to safely cross the intersection. Walking speed assumptions in elementary school areas should be more conservative to account for younger children crossing the street. Newer pedestrian signals, such as the one shown in the image at right, provide countdown clocks which clearly communicate to pedestrians the time remaining to complete the crossing. Here again, the high pedestrian demand during peak hours warrants consideration of special peak hour signal timing to truly prioritize pedestrians.
Limited Exposure - Reducing crossing distance, providing refuge islands, and reducing conflict points can minimize a pedestrian's exposure to traffic while crossing an intersection.

Intersections should be as compact as possible in order to minimize crossing distances for pedestrians. For larger intersections, mid-street refuge islands allow pedestrians to cross one lane or direction of traffic at a time. Right-turn-on-red restrictions can also be used to reduce pedestrian exposure in the crosswalk.

On streets with curbside parking, curb extensions can reduce the required crossing distance and time. Curb extensions, as shown in the image at right, can also make pedestrians more visible to drivers.
Clear Crossing - The crossing path, including sidewalk ramps adjacent to the street, should be clear of all barriers, including utility poles, fire hydrants, and signalization equipment. The crossing path must also be ADA compliant. Compliance is generally an opportunity to enhance intersections with amenities that are both inclusive and attractive, as shown at right.
Enforcement - Presence of security and law enforcement during peak travel periods may be necessary to enforce the low-speed, pedestrian-prioritized environment necessary for these thoroughfares. This is especially true when trying to transform areas to reflect "new" values.

Consider pedestrian presence when selecting the type of control at intersections. Traffic signals, signs, and markings are used to guide and regulate the multi-modal interaction and movements at intersections. Chapter 2 of the MUTCD discusses the merits of several control measures and describes the warrants for each. For example, stop signs are typically used on minor roads intersecting the arterial street in residential areas, as shown at right. Although stop signs can also be used on major arterials, intersections must be carefully designed to ensure that pedestrians waiting to cross are clearly visible and motorists yield the right-of-way when pedestrians are present.

Generally speaking, traffic signals are less common along residential thoroughfares than the others considered as part of this guide. Even so, the MUTCD signal warrants can be used to assess the appropriateness of a traffic signal along residential thoroughfares where they intersect with other higher-volume streets. Effective warrant evaluation necessitates the use of current, comprehensive data for vehicular and pedestrian traffic and direct field observation by the individuals ultimately making the traffic control recommendations.

Meeting some or all of the eight warrants outlined in the manual does not mandate the use of a traffic signal, but this information should be used by local leaders, planners, and designers in decision-making. Warrant 4, in particular, focuses on pedestrian demand and should be given special attention in mixed use environments.

If traffic signals or mid-block pedestrian crossings are present, they should include Accessible Pedestrian Signals (APSs). APSs provide various types of information to pedestrians with vision impairments. APSs can help create great streets that are accessible for all users. Chapter 4E of the MUTCD provides additional information on APSs and their application.

AASHTO's Guide for the Planning, Design, and Operation of Pedestrian Facilities, describes several types of APSs, including:

Audible at Pedestrian Signal Head: a speaker on top of the pedestrian signal head emits a bell, buzzer, cheep, spoken message, or some other audible tone during the walk interval, alerting pedestrians of the appropriate time to cross.
Audible at Push Button: a locater noise is constantly emitted from the push button to identify its location. When the button is pushed, it triggers the emission of a voice message or other noise signal when the walk interval begins.
Vibrotactile: the push button or arrow vibrates during the walk interval, allowing those who cannot see to feel the vibration and know that the walk interval is active.
Transmitted Message: pedestrians wearing a special receiver can hear intersection-specific information, such as the announcement of walk intervals, which is transmitted from an infrared or LED device on the signal head.

Due to the primacy of pedestrians in residential areas, lower vehicular speeds are desirable along the thoroughfare. Lower speeds create less noise and improve the quality of life for residents living along the street. They also make it more convenient and safe for pedestrians along the street.

There are a variety of other intersection design treatments that can help contribute to lower speed environments:

Credit: Charlier Associates

Neighborhood traffic circles (not to be confused with modern roundabouts) are physical circles built in the middle of intersections to slow vehicular speeds down through the intersection.

They prevent through-traffic on the arterial street from driving straight through the intersection by forcing drivers to alter their path of travel around the circle.

If considering neighborhood traffic circles as an intersection design treatment, the following points should be kept in mind:

Landscaping, public art, water fountains, and other treatments can be used in the center of the traffic circle to add aesthetic value to the street. While they certainly can be aesthetically very pleasing, the height of such treatments can impede visibility for pedestrians at the intersection as they try to cross the various legs of the street.
Nighttime lighting in residential neighborhoods is often intentionally darker than other arterial streets to accommodate local residents. This can make it difficult to clearly see neighborhood traffic circles as drivers approach the intersection. Raised cobble stone strips or other such raised pavement treatments in advance of the intersection can be an effective way to alert drivers to the approaching intersection treatment. Advanced signing located in areas of clear visibility are also important in this regard.
Intersections with high left turn volumes should not consider neighborhood traffic circles due to the awkward geometry constraining the left turn movements. Left turning vehicles tend to cut through the left side instead of driving around the circle.

Modern roundabouts can also be an effective traffic calming method for residential streets. Figure 1 below is a generic depiction of typical modern roundabout features:

Modern roundabouts are very different from neighborhood traffic circles. While they both have "circles in the middle of the intersection, they differ substantially on the size of that central island and in the curvature of the intersection approaches and intersection corners. These features are designed to promote the desired speed through the roundabout, in this case lower speeds. Table 1 provides typical values for a variety of roundabout types. Type selection should be made based on the characteristics of the respective residential street. For the residential place types considered in this guide, the rural categories are not applicable.

More detail on roundabouts is provided in FHWA's Roundabouts: An Informational Guide.

Curb extensions are another intersection treatment that can have a traffic calming effect in residential neighborhoods. Curb extensions narrow the width of the road at the intersection, causing drivers to slow down as they approach. They also decrease the length of crossing distance required for pedestrians.

The design of corner curvature, or curb return radii, at intersections has a direct effect on travel speed. Smaller radii create a sharper turn and force drivers to slow down as they navigate the turn. Larger radii have the opposite effect, allowing drivers to navigate the turn at higher speeds. Smaller radii, therefore, are more desirable for residential streets in an effort to keep travel speeds low.

Credit: Charlier Associates

Bicycle travel should be encouraged and prioritized in residential place types. This mode is an efficient, environmentally responsible choice that provides residents a very economical way to make short trips, presuming that good bicycle accommodations are available.

Treatment of bicycle lanes at intersections can be a delicate balancing act due to the variety of conflicts that bicyclists will encounter, as shown at right. In residential areas, bicycle travel should be prioritized at these locations to ensure user safety and to maximize the attractiveness of the bicycle mode choice.

Various intersection treatments are available to accommodate vehicular turning movements while maintaining the integrity of the bicycle lane facility. It is generally appropriate to dash or drop the bike lane striping where merge movements will occur across the bicycle lane. See Chapter 9C of the MUTCD and the AASHTO Guide for the Development of Bicycle Facilities for specific guidelines.
Curb extensions used for traffic calming and pedestrian benefits should not extend into the bicycle lane.

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Source: FHWA Access refers to the demand for vehicular entry and exit to and from driveways and crossroads that intersect with an arterial. These driveways and crossroads are commonly referred to as access points. Access points present a number of planning and design challenges and potential hazards along the roadway. Each access point represents a potential conflict between turning and through-moving vehicles, pedestrians, and bicycles on the thoroughfare, as illustrated in the diagrams at right. Greater access point density increases the number of potential conflicts along the thoroughfare.

Source: FHWA

Access management refers to the regulation of access point location and spacing and is a crucial part of creating a great street that is safe for all modes. Access management is intended to balance mobility for through-traffic and access for vehicles attempting to enter or leave the roadway, while ensuring maximum safety for all users. Typically, a roadway's functional classification guides the location and spacing of access points.

Access management plans must be site-specific and place-based. The figure at right depicts the traditional relationship between access and functional classification.

Source: FHWA

At the top of the functional class hierarchy (principal arterial freeways), mobility is provided at the expense of access; at the bottom (the local road system), extensive access is provided, which limits mobility. Planning and designing great streets requires finding the most appropriate balance between access and mobility, according to place type. While local guidelines can sometimes be useful, standard solutions based solely on functional classification rarely produce desirable outcomes.

Tradeoffs are inherent in every roadway access point decision. Balancing competing interests is critical to successful implementation, and is perhaps one of the biggest challenges in designing great streets. Allowing unlimited access points would undermine the safety and efficiency of the thoroughfare. Conversely, prohibiting all access would render adjacent properties essentially worthless.

Source: FHWA

Access must be considered on a case-by-case basis. The owning transportation agency (the state, county, or local municipality), controls access rights along roadways within a jurisdiction. Most agencies have policies in place to regulate new and existing access point development. Nonetheless, access plays such a critical role in determining the environment along a roadway that planners, designers, and stakeholders are encouraged to carefully examine projects on a case-by-case basis.

Site-specific conditions and community objectives should always be taken into account when deciding how to manage and control roadway access. Specific spacing requirements will vary based on site-specific conditions. The ITE Traffic Handbook Table 10-5 provides guidance for minimum spacing requirements.

MoDOT's Access Management Guide identifies four major goals of access management:

Improve roadway safety
Improve traffic operations
Protect taxpayer investment in the roadway
Create better conditions for non-motorized modes of travel

MoDOT emphasizes that the guidelines are intended to allow for flexibility when necessary, and their overarching goal is to provide a safe and efficient transportation system while balancing the need for access to abutting land uses. Broad standards should not be applied without careful consideration of a project's unique characteristics.

Traffic impact studies should consider the large-scale transportation network (current and planned) before access permits are granted. Developers are typically required to conduct a traffic impact study before gaining approval for new developments. Unfortunately, each individual development usually conducts its own study, failing to capture the cumulative impacts of all proposed developments in the area. In such cases, a project may be approved because its impact on the roadway seems reasonable, but the combined impact of several projects can create traffic problems along the thoroughfare.

Characteristics that influence access in Residential Neighborhoods:

Numerous abutting single-use residential parcels with individual access needs, but relatively low demand for each parcel
Lower travel speeds
Significant pedestrian presence
Possible transit presence

Credit: CH2M HILL

Neighborhood corridors are typically abutted by single-use, residential parcels, as in the image at right.

In many cases, each parcel will have a separate access point, although backage roads or alleys can also be used to provide off-street access.

The relatively small number of trips generated by each parcel typically does not present a major conflict to through-traffic. These thoroughfares may serve as transit routes if the abutting neighborhoods provide sufficient density.

Credit: CH2M HILL

Crossroad access points can be signalized or unsignalized.

Regular intersection spacing is important for overall efficiency and traffic progression along the thoroughfare, especially for signalized intersections, as shown at right.

In residential areas, traffic signals are typically less common. If multiple signals are present, they should be spaced at least one-quarter mile apart. Unsignalized intersections occur more frequently along residential streets.

Credit: CH2M HILL

Typically, traffic on the lower volume/minor road is controlled by a stop sign, allowing traffic on the major thoroughfare to flow freely (as shown at right).

Unsignalized crossroads with more traffic and a greater number of turning movements (> 50 vph in the peak hour) should consider adding deceleration lanes on the thoroughfare street.

Deceleration lanes allow vehicles to pull out of the through-travel stream before turning, resulting in safer traffic operations on the thoroughfare.

This treatment may necessitate acquiring additional right-of-way, and the potential impacts to adjacent parcels should be considered.

The lower travel speeds in residential areas improve a driver's ability to perceive and react to conflicts created by access points. Because most residential driveways have a relatively low daily demand and present minimal conflict to through-traffic on the main thoroughfare, access points may be provided more frequently than in place types with higher travel speeds. Spacing requirements will vary based on site-specific conditions and local codes.

Although the number of driveways along a residential thoroughfare is generally proportional to the crash rate, the lower demand per driveway experienced along residential streets renders each access point less of a safety concern than those in a high density commercial environment, for example.

Shared access, or the consolidation of access for multiple residents, can improve the efficiency and safety of residential thoroughfares, especially in areas with substantive safety concerns. Driveway consolidation also reduces the quantity of impervious surfaces in an area, thus reducing the impact on stormwater management requirements (see the Drainage section of this guide for more details).

Plan for pedestrian and bicycle movement. These thoroughfares should prioritize pedestrians along the street, and especially at the intersections. Intersections will provide the vast majority of vehicular access along the street, so it is vitally important to provide safe, efficient crossings and refuges for pedestrians at these locations. See the Intersections section of this guide for more detail.

The pedestrian environment along these corridors must be prioritized. Special signage to remind drivers to watch for pedestrians, as shown in the image at right, can be useful in managing this conflict when curb cuts and driveways are required.

Reduce points of conflict. Bicycles will also be at conflict with access points along the corridor. Whether cyclists travel along a marked bicycle lane, a wide outside lane, or along a shoulder, they will inevitably have to cross driveways and intersections. Where regular bicycle use is expected/desired, driveways should be limited. Drivers attempting to enter the thoroughfare from a driveway are often fixated on traffic approaching from the left, and may edge out onto the thoroughfare without looking back to the right to check for pedestrians. Bicycle-specific measures should be provided at intersections to prioritize bicycling at these locations.

The crossroad access points/intersections will generally be of two types: signalized or unsignalized. Both types have important characteristics to consider in the development of great streets. For signalized intersections, regular spacing is beneficial for the efficiency of the greater thoroughfare. Minimum signal spacing for these place types should be one-quarter mile. Signalized access points can provide a safer pedestrian environment by including pedestrian crossing signals and, if appropriate, restricted turning movements during pedestrian crossings.

Unsignalized intersections are more frequent and create more potential conflicts between cars, pedestrians and bicycles. They are usually controlled by stop signs on the minor road without stopping traffic on the thoroughfare itself. They may represent a minor road crossing, a parking lot entrance, or an atypical larger parcel entrance. Pedestrian visibility is always important, but even more so at unsignalized intersections.

Access points create conflicts for through-moving vehicles and pedestrians. Drivers are typically focused on vehicular traffic when attempting to enter or exit a particular thoroughfare, and may fail to see a pedestrian crossing the driveway. Drivers attempting to enter the thoroughfare from a driveway are often fixated on traffic approaching from the left, and may edge out onto the thoroughfare without looking back to the right to check for pedestrians. In areas with a significant pedestrian presence, the number of driveways should be minimized to the extent practicable. At higher volume access points, signage reminding drivers to watch for pedestrians can be used to minimize conflicts.

Consider transit access. In these place types, transit may be present. Even if it is not currently, it may be in the future. Mobility for transit is important to consider, and it requires careful examination of access along the street. Transit lanes, queue jumpers, and bus stop location/design are all important elements to be considered along neighborhood thoroughfares.

The transit lane (could also be a shared transit/HOV/bike lane) condition provides a continuous bus-only lane throughout the entire corridor. These concepts can be very effective in prioritizing mobility for other modes, but they do have impacts on abutting access requirements. When such measures are provided on the outside of the travel way, they will conflict with every driveway along the corridor.

Managing the location and spacing of such driveways, then, is imperative in order to encourage transit along the street. Failure to do so will inhibit the intended prioritization of transit. Spacing guidance should be developed on a case-specific basis, and it should be coordinated with local businesses and residents whose parcels abut the street. When transit lanes are provided down the center of the street, as in the image at right, conflicts with adjacent driveways are lessened. The center location, however, creates another set of conflicts to manage the movement of pedestrians to and from median transit stops. Pedestrian crossing, perhaps even mid-block pedestrian signals, should be provided in close proximity to median transit stops.

Consider access to bus stops. Such access must be provided efficiently and safely, without degrading operations for other modes along the corridor. Three general options are available for bus stop location: mid-block, near side, and far side. The tables at right describe the advantages and disadvantages to consider for each of these conditions. Each specific site condition will have characteristics that influence the best choice for bus stop location, and it is imperative that they be examined as such. There is no "one size fits all" solution that should be applied blindly across an entire corridor.

Regardless of location, clear and visible signing should be present to aid pedestrians in locating nearby bus stops. Chapters 9 and 10 of the ITE guide Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities provides additional information on these subjects.

Use raised medians, when appropriate. Ideally, thoroughfares in residential areas will have slow vehicle speeds and narrow crossings to facilitate pedestrian ease and safety. However, it is possible that a thoroughfare through a residential area could be improved with the use of raised medians.

Raised medians reduce the number of access-related conflicts by restricting left turn movements to the access points across from an opening in the median. Access to driveways is confined to right-in, right-out movements, reducing the number of potential conflicts from nine (9) to three (3) at a standard 3-legged intersection (see Oregon PDF for additional detail on right-in, right-out channelization design).

Medians can help create a more urban-style access management plan but they also create issues for drivers seeking access to both sides of the thoroughfare. U-turns are generally not recommended in areas with a significant presence of pedestrians and bicycles because they reduce predictability. Careful network planning is important to accommodate the desired travel patterns and facilitate access to both sides of a thoroughfare.

Raised medians can help reduce vehicle speeds by creating more visual friction in the thoroughfare.
Raised medians provide opportunity for pedestrian refuges, when crossing distances are long. Raised medians with this purpose must be carefully designed, including a preferred minimum refuge width of 6 feet if pedestrians are intended to remain in the refuge during a signal cycle. These medians should extend beyond the crosswalk towards the intersection for pedestrian safety.
Design of the refuge should include application of turn templates for trucks and the design vehicle for u-turns. Reflectors and raised delineators as well as the use of colored concrete can increase the visibility of the median refuge as well as the pedestrians using it. The figure below/at right shows a pedestrian refuge island that addresses some of these safety concerns.

The image on the left is a collage of pedestrian refuge designs from cities throughout the U.S. and Europe. Although wider refuges are desirable, narrow width (e.g., 4-foot-wide) pedestrian refuges do meet minimum width requirements identified in many of the U.S. documents on urban thoroughfare design.

AASHTO's "Policy on Geometric Design of Highways and Streets" (2001) says that 4 feet is the minimum width. ITE's Design and Safety of Pedestrian Facilities (March 1998) states that the minimum width for pedestrian refuge island is 4 feet.
Raised medians provide the opportunity for attractive landscaping (see the Safety section of this guide for more information about issues related to trees or other fixed objects in the median). Landscaping, along with other objects in the median should allow for the recommended clear zone. AASHTO recognizes that "space for clear zones is generally restricted" and suggests that a "minimum offset distance of 18 inches should be provided beyond the face of the curb."

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