Traffic Calming & Cyclists
In the planning, design, and operation of transportation facilities bicyclists and pedestrians should be included as a matter of routine and the decision not to accommodate them should be the exception rather than the rule. There must be exceptional circumstances for denying bicycle and pedestrian access either by prohibition or by designing highways that are incompatible with safe, convenient walking and bicycling. --FHWA
Guiding Principles Cyclists are legitimate and historic users of all roads except limited access highways. Road designs must accommodate cyclists as primary users and must never discourage them. Cyclists and pedestrians act as traffic calming devices by their presence. Bicycle facilities can add to the traffic calming effect if properly designed.
Road Blocks An extreme example of traffic calming, road blocks do indeed cut down on motor traffic but they also have the unintended and unnecessary effect of blocking cyclist traffic.
Bike Hostile Traffic Calming In response to community concerns these traffic calming devices were installed but without taking into account cyclists. Bikers must exit the bike/parking lane near the narrowed entrance to the intersection. While this may not bother experienced adult cyclists, children may not have the judgment to cross the road safely.
Case Study Harmony Rd. The original intersection Cut through traffic was dense and high speed, preventing residents from crossing the road. A parking lane served also as a bike lane which provided an excellent level of service to cyclists.
The Solution Neckdowns almost completely take up the bike lanes forcing cyclists to either ride in narrow, trash filled gutters or swerve into the traffic lanes. The traffic lanes are not significantly narrowed.
An Alternative Solution The small traffic roundabout forces car traffic to slow down while leaving room for cyclists. Painted bike lanes visually narrow road and establish cyclists right of way in it.
Chicanes As the chicane blocks most of the bike lane, the cyclist is forced into the traffic lane just as an approaching motorist is focused on 1) negotiating the narrow pass and 2) oncoming traffic. Conflicts and accidents are likely to be increased by this design. Traffic is slowed only in the chicane as motorists typically speed up afterwards to make up for lost time.
Chicane - Modified The modified chicane blocks are narrower, only partly blocking the bike lane. The cyclist can ride through without entering the main traffic lane. However, the narrowed section of the bike lane will act as a trash collector without frequent sweeping. Cyclists may still have to ride in the traffic lane to avoid trash. Car traffic is still only slowed momentarily at the chicane, speeding up afterwards.
An Alternative Design The bike lanes are colorized, visually narrowing the road to motorists which causes them to slow the entire length of the road. Speed cushions further re-enforce lower speed but allow wide emergency vehicles complete access. Note: smaller speed cushions may be necessary in bike lanes to discourage motorists from swerving around main cushions.
Wide Shoulder Chicanes Where there are shoulders wide enough to allow a full width bike lane and chicanes, chicanes may be appropriate. Here, motorists are forced into a shallow S curve while cyclists still have a 6 foot wide bike lane. Colorized, perhaps even raised, bike lanes visually narrow the road for motorists decreasing the tendency of drivers to speed up after the bend. Trash accumulation may still be a problem requiring periodic cleaning next to the chicanes.
Cityscape Two way bike lanes accommodate cyclists who often now ride on sidewalks. Forward stop zones allow cyclist turns while protecting pedestrian crosswalks. Bumpouts, placed so as not to interfere with cyclists, shorten crossing times for pedestrians.
Conclusions Delaware desires to promote alternative transportation. DelDot is committed to preserve and enhance bicycle access to all roads. Cyclists must be considered primary users throughout the design and implementation of all traffic calming projects. Cycling experts should review all applicable projects prior to finalization of design.
Delaware s Future Cyclists Thank You!
Credits Narration: Main Narrator...Christopher R. Law Female Voice...Sarah Law 2nd Male Voice Christopher R. Law II Art Work and Photos: Christopher R. Law Other Contributors: Mario Nappa, Frank Warnock, Don Carbaugh Christopher R. Law 2004. All rights reserved. This presentation may be reproduced, either in its entirety or in part, for educational purposes only, provided the source is properly attributed.