Ever been sideswiped by a car on a narrow street or honked at while riding on a bicycle boulevard?
Centerlines are the double yellow lines down the middle of the road and they are used to keep cars to the right side of the roadway, out of the way of on-coming traffic. They certainly help cars on rural roads and curvy roads, particularly at night on these streets. But how do they affect bicyclists? I don’t like ’em! I feel I get honked at and sideswiped more on streets with centerlines.
On roads that are popular bikeways, centerline stripes have the exact opposite effect needed to make streets safe for bicycling. They encourage motorists to stay in their travel lanes and maneuver to pass cyclists closely, rather than giving three feet that is the minimum safe passing birth. A preferable scenario is that motorists move left 3-5 feet into the adjacent, on-coming lane to safely pass you while riding your bike in the travel lane. Hence a contradiction in traffic engineer tools–well designed bikeways encourage motorist to pass safely to the left of a bicyclist, while centerline strips encourage motorists to pass much more closely. Have you even been sideswiped on a narrow street? On top of this, my anecdotal experience is that motorists feel I’m ‘in their way’ on a street with a centerline, and thus they are more likely to honk at me to get out of the way. This doesn’t discourage me from riding, but probably has that effect on many potential bicyclists.
The Manual on Uniform Traffic Control Devices (MUTCD) states that roadways with 6,000 cars per day or more shall have a centerline stripe that is yellow in color. If it is a double-yellow line (like the one shown in the photo to the right on the Milvia Street Bicycle Boulevard in Berkeley), cars are not suppose to pass on the left. Below, 6,000 cars/day, the installation of a centerline is optional at the traffic engineer’s discretion. The MUTCD never considered the effect on bicycling when developing this rule-never! Because of this, I feel the centerline rule should be ‘advisory’ on bikeways and not mandatory.
Some traffic calming manuals suggest that centerline striping actually reduces vehicle speeds, due to a visual narrowing of the travel lane. However, in the United Kingdom, traffic engineers believe that centerline stripes actually increase travel speeds because they draw a motorist’s attention farther down the road and away from the immediate surroundings, which has a speed increasing effect. I subscribe to the latter view, but it seems the jury may still be out on this one.
Either way, centerline stripes certainly encourage motorists to stay close as they pass nearby to cyclists, which is a dangerous thing, and should be discouraged. Should bikeways have centerlines?
You have probably seen Sharrow markings used on streets in the East Bay. They are used on bikeways where planners cannot figure out any other way to stripe a bike lane (there are issues with this planing approach). If you haven’t seen a sharrow, go to Gilman Street in Berkeley, Telegraph Avenue in Berkeley, or Foothill Blvd in Oakland. However, Sharrows have never been studied in connection with centerlines. They were originally studied and proved somewhat effective at encouraging cyclists to move farther out from parked cars and to encourage motorists to move farther to the left of cyclists–both a good thing. But the studies did not include an analysis of whether the roadway included centerlines (the analysis also did not include a study of traffic speeds, unfortunately). Thus, sharrows say move left while centerlines say stay right. Traffic indicators should not send contradictory messages to motorists.
The East Bay Bicycle Coalition is requesting the Federal Highway Administration to further study the issue of centerlines and bikeways and hopefully rule that bikeways not include centerlines. It’s a small step, but an easy step, toward streets that are actually safe and comfortable to ride on.
Any thoughts?
Dave Campbell
Advocacy Director
East Bay Bicycle Coalition
We will be returning each Tuesday with a new subject for you to ponder and provide us feedback. We started this trend a couple of weeks ago with our SuperSharrows blog, asking for your feedback on Long Beach’s new bikeway designs–with several of you commenting on the concept.