Neighborhood main streets are a nexus of neighborhood life, with high pedestrian volumes, frequent parking turnover, key transit routes, and bicyclists all vying for limited space. Main street design should limit traffic speeds and create a narrower profile with frequent, high-quality pedestrian crossings. In recent years, many main streets have been significantly improved through road diets and the conversion from 4 to 3 (or 6 to 5) lanes of travel with bike lanes and a center turning lane or median.
Existing Conditions
The illustration above depicts a main street with 4 lanes of traffic. With medium traffic volumes and high pedestrian activity, the street has significant potential for regeneration as a retail district, yet currently under performs for those who shop, eat, and walk there. Frequent destinations have resulted in multiple turning and weaving conflicts along the street.
14-lane configurations have been shown to increase rear-end and sideswipe vehicle crashes and pose a higher pedestrian crash risk.1
Recommendations
The street illustrated above depicts a 64-foot roadway within a 94-foot right-of-way.
While road diets are not appropriate on all 4-lane cross sections, streets carrying up to 25,000 vehicles per day function effectively with 3 lanes, depending on the traffic volumes of nearby adjacent streets.2
Road diets can improve traffic flow and reduce conflicts with turning vehicles, while increasing a road’s efficiency by channeling turning vehicles out of the through lanes. Streets designed with either 2 lanes or a 2-way left-turn lane can cut crash risk by nearly half.3
As part of a full reconstruction, consider widening sidewalks, especially when they have previously been narrowed in favor of additional travel lanes.
2Turn lanes can help to eliminate weaving conflicts on 4-lane roads. As an alternative to the illustration above, a 6-foot pedestrian safety island can be retained in the above configuration by tapering the bike lane buffer near the intersection and shifting the through lanes to the right.
3The application of a road diet may be carried out in two phases, the first consisting solely of striping and a center turn lane, and the second, of medians and plantings to complement the center lane.
4From an economic standpoint, road diets often rank favorably with business owners and have a positive impact on local business activity.4
5Bike boxes help cyclists make left or right turns by placing them in front of traffic at a red light. On streets with higher traffic volumes, cyclists may choose to make a two-stage turn.
6Parklets are ideal for neighborhood main streets with active storefronts, heavy foot traffic, and lots of retail activity.
7Streets with both heavy freight and parking demand, as well as on-street bike lanes, benefit from dedicated loading zones near the intersection. Loading zones help reduce obstruction of the bike lane and make deliveries easier for businesses. Loading zones can be striped and signed, or managed for off-peak deliveries.
- Evaluation of Lane Reduction ‘Road Diet’ Measures and Their Effects on Crashes and Injuries (Washington, D.C.: Federal Highway Administration, Highway Safety Information System, 2010). ↩︎
- Nikiforos Stamatiadis and Adam Kirk, “Guidelines for Road Diet Conversions,” (University of Kentucky, 2012). ↩︎
- Dan Burden and Peter Lagerwey, “Road Diets: Fixing the Big Roads,” (Walkable Communities, Inc., 1999). ↩︎
- Cullen McCormick, “York Blvd: The Economics of a Road Diet,” (2012). ↩︎