Tuesday, April 20, 2010

Speed Hump Treatment - Day St. in Jamaica Plain, MA


Day Street is located at one of the exits for the turning circle where Day St, Perkins St, and Centre St intersect and extends to the intersection of Walden St. It serves a predominantly residential area and also a school and park about midway on the roadway. The street appears to need repairs along its entire length. The pavement markings are worn down and in some cases missing sections of markings. The street has parking on one side and bears just enough room to fit two vehicles passing each other. The amount of travel space may seem more narrow in some sections, from a comfortability point of view, and drivers parked their vehicles up on the curb in fear of being ‘side-swiped’ by passing vehicles.

There are speed humps installed on the street to calm traffic moving through this area. The intent of the speed humps is too slow down traffic due to the residential neighborhood and nearby school and playground. The conditions that may have warranted the installation of the traffic calming instruments, speed humps, may have been due to drivers operating at high speeds on this roadway. With the narrow travel space and dense residential area, operating at high speeds is clearly a safety issue. Other conditions that may have supported the installation of speed humps :

  • The curving alignment creates limited sight distance while navigating Day St.
  • Areas of the street where there are no lane markings cause drivers to misuse the available space and encroach on oncoming travel lanes
  • Since this is a predominantly residential area, reducing the speed will cater to the safety of pedestrians
  • The presence of the middle school and playground where children will frequently walk Day St.
  • Increased reaction time for drivers in case of a driver opening the door of his parked car or pedestrians crossing the roadway

The speed humps did slow vehicles down on Day St. I personally drove the street from start to end and had to slow down at each hump. Some drivers were observed approaching the speed humps, drivers did slow their vehicles when having to go over the humps, slowing traffic traveling down Day St. (see video at bottom of post). A couple of drivers were observed accelerating quickly between speed humps, but this was not common. The fact that it did happen causes me to question the design distance for the humps, why is there enough room for a driver to speed up in between treatments?

I also found that there was only one speed hump near the school zone on Day St. The treatment was a raised sidewalk. I found this interesting because if desired, a driver can speed along 90% of the school zone without deterrents. I did observe the street during out of school hours, but the length of road that is open seems unsafe since traffic calming was used to deter speeders on this road.

The installation of another speed hump near the school zone should be evaluated, it does not appear safe to me that cars can speed alongside the school zone. I wasn’t able to observe the actions of drivers to make a more complete evaluation because the observation was performed outside of school hours and during a non peak period.

The goal of calming traffic speeds on Day St. was a success in my opinion. From observing drivers during a non-peak period accelerating quickly between speed humps I can imagine how traffic may have operated on Day St. before the speed humps were installed. Granted, the road is narrow and while I drove it myself, I found it very uncomfortable to accelerate to speeds more than 25 MPH, but with the dense residential area and school zone, I think ensuring the calming of vehicle speeds on this street is appropriate.


  1. The effectiveness of speed humps depends heavily on some critical dimensions: height and length of the humps, spacing, how many there are. It is disappointing that the evaluation doesn't provide any measurements of these critical dimensions. Also, success is evaluated by speed, or how often cars travel faster than the intended speed; this should have been observed and reported more carefully.

  2. Nice blog, really I impress for your blog. I got more information about Speed humps . This type of speed humps are very urgent for all drivers.