Road Diets and Safe Street Design

By Ian Watson

In a time where cities are striving to become more pedestrian and bicycle friendly, it is important for communities to consider adoption and implementation of safe street designs. These types of developments integrate bicycle and pedestrian infrastructure to maximize use for all modes of transportation. There are several components that make up these designs.

A bicycle corral adjacent to an intersection helps drivers see pedestrians crossing the street.
A bicycle corral adjacent to an intersection helps drivers see pedestrians crossing the street.

Every foot counts in constrained urban locations, and policies that promote wider travel lanes are less safe. Motorist lanes are normally about 10 feet wide, a design that discourages speeding. Some cities designate 12-foot lanes for buses and trucks, which can encourage drivers to speed. Research has shown that providing narrower lanes can manage speeds without having to sacrifice any element of safety. Wider lanes create extra challenges for pedestrians, including increased exposure to traffic and walking distance at crosswalks. Parking lane space should also be considered in the street layout dimensions. Whereas main travel lanes are usually condensed, wider parking spaces (7-9 feet) can actually serve multiple purposes. Outside of parking, there is enough space for industrial loading and bicyclist activity.

Curbside space is not always used to its full potential. By reducing the amount of on-street parking, especially parking spaces immediately adjacent to intersections, other functions can be put in its place. Sidewalks can be expanded through the use of planter beds and bollards to ease pedestrian congestion. Bike corrals can be placed in former parking spaces at intersections to increase pedestrian visibility to turning cars. Wider curbs decrease the distance that pedestrians travel on crosswalks and also decrease their exposure to traffic. The tightening of intersection curb radii is another method for maximizing curbside space. It encourages slower turning speeds and decreases walking distance between sidewalks. Extensions also reduce basic roadway width and can be used as a signal to drivers that they are entering a neighborhood street.

A curb extension
A curb extension

There are also techniques that can be used to calm vehicle speeds through physical and psychological road configurations. Pinchpoints and lane shifts are two versions of curb extensions that greatly reduce the speed at which motorists can go. Pinchpoints expand sidewalks and take the place of regular on-street parking. Lane shifts are used to horizontally deflect vehicles and may be incorporated with parking. The speed hump design vertically deflects traffic with a slight incline in the road. It can be also used as a small midblock crosswalk for pedestrians. A sidewalk design that psychologically reduces traffic speed is the inclusion of greenery. A lineup of trees parallel to the road can narrow a driver’s visual field and create a sense of caution.

Several municipalities and counties across New Jersey are taking action to improve safety through the use of road diets, and the New Jersey Department of Transportation supports road diets as a strategy to reduce crashes. NJDOT’s Bicycle and Pedestrian Resource Center regularly participates in road safety audits throughout the state in the spring, summer and fall, activities that bring transportation professionals together to explore options to improve traffic safety through street redesign such as road diets. In 2014 New Brunswick implemented a quick road diet on Livingston Avenue and is now proposing a permanent road diet on the entire length of the road. Montclair is also keen to implement a road diet on Bloomfield Avenue, a major road that slices through its downtown, with an expectation that it could decrease traffic crashes by 19 percent. As a final example, suburban Somerset County received a grant in 2015 from the US Department of Transportation’s Local Safety Program – through the North Jersey Transportation Planning Organization and NJDOT – to implement a road diet on Promenade Boulevard/Route 685 in Bridgewater. The four-lane road has been reduced to two lanes and a center two-way left-turn lane. These changes will help decrease both pedestrian and vehicle crashes on the corridor.

 

Sources:

Urban Street Design Guide, National Association of City Transportation Officials

Making Safer Streets, New York City Department of Transportation

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