Thursday, April 26, 2012

Crosswalks that work and that don’t work: Harvard St. @ Green (Brookline) versus Route 9 @ Norfolk or Dunster

Chen (Cheyenne) Chen

Crosswalks that work and that don’t work: Harvard St. @ Green (Brookline) versus Route 9 @ Dunster

Harvard St. is a two-way street without median barrier. Each direction only has one travel lane.  There are one parking lane and one bicycle lane on each side. The functionality of Harvard St. is collector road. Traffic volume is around 800 veh/h. Green Street is a one-way street shared with bicycle and one parking lane on one side. It is a local street. From the picture below we can see the area is mixed commercial and residential use together. The intended users are commuters and shoppers.

Googlemaps link:

Current Pedestrian Status
The speed limit of Harvard St. is 30 mph. The width of Harvard St. is around 48 feet. Pedestrian generally take 10 sec to cross the street.  Pedestrian volume is 500 ped/h around noon time (See the video below). The important thing is that the pedestrian volume is kind of high around this area, which forms pedestrian priority in the crosswalk. There is a pedestrian yield sign placed in the center of the road to alert driver to slow down. Thus, driver’s expectation is to slow down in this area to yield pedestrians who are walking on the crosswalk.

Moreover, there is no left turn permitted. This rule simplifies the traffic flow and reduces the conflict of pedestrian and turning vehicles.  Moreover, the number of travel lanes merges from two lanes to one lane from Beacon Street. This reduction physically forces drives to slow speed.  Based on all these factors, this crosswalk does work well for all of pedestrian, bicyclists, and motorists.


Route 9 is a two-way street with median barrier. Each direction has two travel lanes. The speed limit of Route 9 is 40 along this section. The function of Route 9 is mobility. Dunster Rd. is a two-way local street without lane line. Its function is accessibility. The traffic volume ranges from 2000 veh/h during noon time. The intended user of this crosswalk is the local residents.

Googlemaps Link:

Current Pedestrian Status
This intersection is two-way stop control in Dunster Rd.  The width of Route 9 is around 56 feet. Some vehicles are parking along two sides of this route. Here the road is straight. Driver’s expectation on speed is very high along this section. Pedestrian volume is close to zero during most time of the day and high traffic volume. Thus, under most conditions, pedestrian should yield fast vehicles. It takes around 10 seconds to cross Route 9 but it may take around 20 min for a pedestrian to find accessible gap to cross the street, which is very inconvenient for pedestrian and can cause some safety issue because of the high speed.

The two crosswalks do work for two different intended users. The pedestrian volume is high at Harvard St. @ green thus vehicles are designed to yield to pedestrian. And the pedestrian volume is close to zero at Route 9 @ Dunster . Some recommendations could be used for the crosswalk at Route 9 @ Dunster to improve pedestrian safety.

·         Install push button pedestrian signal.

·         Sharktooth yield bars can be added before the crosswalk.

·         Soft (thermoplastic) rumble strips can be added to alert motorists of an approaching “stop” or “slow down” ahead.