Route 9/Parker Street
From Newtonstreets
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Problems
Current state
There are three, related problems at the Route 9 (Boylston Street) and Parker Street interchange.
The volume and nature of traffic exiting and entering Route 9 makes it very difficult for pedestrians and bikers to cross over Route 9 along Parker. This is particularly troublesome because of the proximity of Newton South High School, Oak Hill and Brown Middle schools and Newton Centre to this intersection. It is difficult for students who live north of Route 9 to walk or bike to school because of the intersection. And, the difficulty of crossing Route 9 makes it less attractive for residents south of Route 9 to walk to Newton Centre.
The pedestrian problem is a function of an intersection that can be overwhelmed by the volume of traffic entering and exiting Route 9 during peak traffic on Route 9 or on Parker Street. This volume itself, is a problem. During busy periods, it is very difficult to turn onto Parker from the Route 9 exit ramps. It is particularly difficult for drivers exiting Route 9 eastbound and turning north (left) on Parker or exiting Route 9 westbound and turning south (left) on Parker. In both cases, drivers have to cross a one lane of busy traffic and merge into a second lane of busy traffic.
And, the traffic on Parker Street is getting so high that it is becoming increasingly difficult to exit the side streets (Walter, Daniel, &c.) to enter Parker Street.
Additionally, there are no curb cuts on the bridge sidewalks, making it more difficult for pedestrians and cyclists and impossible for the disabled.
Future changes
The problems stated above will be exacerbated by any increase in traffic on Route 9.
When the Sam White property is developed, Route 9 volume will not only increase, but there will be a new demand on the bridge: traffic from east of Langley that needs to get to the now-Sam White property. That traffic will have to use the Parker Street bridge to do a U-turn. This may merit reconsideration of the Parker Street U-turn option, which was proposed in the Route 9 corridor study. See below.
Goals
The goals of any treatment of the interchange should be, in order:
- Ensure pedestrian and bicyclist safety in the interchange
- Make it comfortable for pedestrians and bicyclists to cross over Route 9 on Parker Street
- Ensure motor vehicle safety through the interchange
- Not cause cut-through traffic on nearby side streets
- Not cause crosswalks or side streets to be blocked by traffic backed up on Parker Street
- Not materially degrade traffic on Parker Street
- Improve traffic flow on, to, and from Route 9
Proposed Solutions
Rebuilding the Bridge
Three factors should make rebuilding the bridge a real option:
- The current state of the bridge. It's old and deteriorating.
- The need to make changes to ameliorate the effects of the Chestnut Hill Square development.
- The need to make changes to ameliorate the effects of the proposed development on the Sam White property, which are not just added volume, but a very specific congestion-causing use case.
In light of the confluence of factors, the commonwealth and the city should give serious consideration to rebuilding the bridge.
New Crosswalks
There appear to be (at least) three problems with pedestrian crossing:
- High volumes of traffic without obvious gaps for pedestrian crossing (at least during peak periods)
- Lousy sightlines
- Motorists who are preoccupied with the challenges of merging with traffic, crossing a lane of traffic or both don't pay attention to pedestrians
One way to help deal with the problems is to move the pedestrian crossings (for at least the offramps) so that they are off of Parker itself.
Specifically, on the westbound offramp, move the crosswalk away from Parker Street:
- Move it west, near the intersection of the offramp and Jackson street.
- Make the relocated crosswalk a raised crosswalk.
- Connect it to a new sidewalk that would go along the south side of the ramp from the point of the crosswalk up to Parker Street.
- Add bollards or other means to direct pedestrians east to the crosswalk and discourage/prevent pedestrian crossing at the current northeast crosswalk.
Take the corresponding steps on the eastbound offramp.
On the picture below, the yellow lines indicate new sidewalks. The white ladders are proposed crosswalks. The proposed changes are not necessarily to scale or optimally located. The purpose of the picture is to illustrate the concepts.
By moving the crosswalks, motorists would be less occupied when they confront pedestrians, as they wouldn't yet be worrying about merging with traffic. In both instances, the sightlines up the ramps are excellent, so motorists would have plenty of time to absorb that there was a raised crosswalk and that there may be pedestrians.
One challenge: moving the crosswalks would require state involvement as the ramps are under state control. This should not be fatal.
There may also be an issue with the height of the fence on what would become the traffic side of a new sidewalk. Again, this should not be fatal.
It is less clear that this solution would work on the onramps, as motorists would not have the same notice of the crosswalk. But, it should be considered.
Pedestrian Crossing between Langley and Parker
Better connect the south and north of Route 9 between the two major intersections. A bridge?
A connection near Dudley Street would create a better connection from one side to the schools on the other side.
The TWLTL Solution
The traffic problem may be (partially) solved by creating a third lane on the bridge over Route 9, a Two-Way Left-Turn Lane (PDF). Another report (PDF). A Two-Way Left-Turn Lane (TWLTL) would convert the single task of turning left onto Parker Street from either offramp into two tasks:
- Cross a lane into the TWLTL
- Merge from the TWLTL into traffic
It's not clear whether the current bridge is wide enough to have a third lane. One option would be to eliminate one or the other sidewalks and build a separate pedestrian bridge. If necessary, widening the bridge to add TWLTL or adding a separate pedestrian bridge seems feasible because there is room east of Parker Street to begin the "dip" under Parker Street sooner.
There may not be sufficient room to create a long enough TWLTL.
The signalled solution
One plan, under consideration as part of the changes to be made with the Chestnut Hill Square development, is to add one or two signals. Initially, there was some concern that New England Development proposed lights simply because they were mentioned in a CTPS study of the Route 9 corridor, almost as an aside. The proposal clearly merits a full study. It now appears that New England Development and the city (and its consultants) are studying the interchange.
It is not clear how two signals could be timed so that left-turning traffic from the off-ramps doesn't negate any benefit created by a gap to allow left-turning traffic from the off-ramps.
Another proposal is a single signal on the south side.
Concerns with the signals:
- Timing that would allow pedestrian-only gaps for crossing both ramps
- Backing traffic on Parker:
- Blocking crosswalks (especially the school-route crosswalk at Daniel Street)
- Blocking exit from sidestreets
- Creating incentives to use side streets to avoid backups at Parker Street
- Degrading the level of service on Parker Street
- Having signals during periods when volume on Parker Street and the ramps is such that no signal is necessary.
On the last point, signals should be flashing yellow (on Parker) and flashing red (on the ramps) except when they are really needed.
Roundabout
Avoid signals. Rebuild the bridge as a roundabout/rotary.
The current, unsignalled interchange is clearly not working. A signal or signals introduces all of the problems associated with traffic controls.
If this were not a bridge, but an intersection with five (!) inputs and four outputs, a rotary would be at or near the top of the list of recommended solutions. Right of way is probably not an issue. The width of the bridge is.
A rotary would require a bridge rebuild, but would be the best solution.
U-Turn Only Bridge
This idea was originally proposed in the Route 9 corridor study as a way to deal with the congestion at Langley Road. The proposal involved closing the jughandle at Langley Road and having westbound traffic that needed to go eastbound continue to Parker, where there would be a dedicated U-turn lane added to the east side of the bridge.
The U-turn lane to solve the Langley street problem appears not to be part of any current plans. But, the proposed development of the Sam White property raises a new problem: traffic from points east of Parker Street that needs to get to the new development. With the current configuration of the Parker Street overpass, such traffic would exit Route 9 eastbound, turn left on Parker Street, and then turn left onto the westbound on-ramp.
This promises not only more volume on Route 9, but particularly congestion-causing traffic.
