Free the ramp
State should give Silver Line quicker tunnel access
- See all »
- See all »
- See all »
- See all »
- See all »
If you are not a frequent user of the Silver Line to Logan International Airport, you may not appreciate how the ramp is supposed to work. The ramp comes directly off the Massport haul road adjacent to the MassDOT Operations Control Center and State Police complex. When the Silver Line bus exits the tunnel from South Station at D Street, it stops at a traffic light, then proceeds across the street where it stops again to change power modes. The bus then proceeds to the tunnel, using a long and circuitous route that actually passes directly by the ramp into the Ted Williams Tunnel. The bus would save a lot of time and get riders to Logan more quickly if it simply went down the ramp into the tunnel.
This past summer I sent emails to agencies involved in the operation of the tunnel and, in particular, the ramp. My inquiry was met with a response from a staffer at MassDOT, who gave me several reasons why the MBTA cannot use the ramp which was explicitly designed for it. Here are the reasons given, and here’s why none of them hold water:
MassDOT: “It’s important to note that this ramp was constructed to serve public safety and MassDOT vehicles and was never designed to service normal buses, let alone the much longer and articulated Silver Line buses.”
MassDOT: “We have found that there are several factors that make this location unsafe and problematic for bus service, including a very small turning radius and narrow configuration, a steep grade that decreases an average of 6 percent over a mere 600-feet, and high retaining walls that restrict sight distance and visibility.”
The turning radius is a red herring. Not only is the turning radius in to the ramp significantly less severe than the turning radius only a few hundred feet away on Silver Line Way where buses turn back, it’s nothing compared to the buses making a right turn from Washington Street to Temple Place downtown. Now, for the grade. First of all, a 6 percent grade is within interstate standards. But this isn’t an interstate highway, it’s a restricted-access ramp. There’s no reason a bus couldn’t navigate this; and articulated buses in other cities are certainly able to go up and down steeper hills. We’ll cover the restricted visibility in a moment.
MassDOT: “Additionally, at the bottom of the ramp the buses would have to stop due to the High Occupancy Vehicle (HOV) lane and the mainline traffic, and there is very little merge distance in that area for these types of vehicles.”
So, yes, there is not a lot of merge distance here. But there are two flaws with this argument. One is that the Silver Line ramp and the HOV lane have very low traffic numbers, so it’s not like trying to merge two heavy traffic flows together. The second is that there are ramps in frequent use which have significantly shorter merge distances than this one, and which see significantly more traffic than the lane this merges in to, but we are not closing them because of safety concerns.
In regard to traffic counts, once the Silver Line Gateway opens there will be a bus to the airport every eight minutes and to Chelsea approximately every 10 minutes at peak hour, so a bus would use this ramp approximately every four or five minutes in aggregate. The lane which it is merging into, the HOV lane to the airport, generally sees fewer than 5,000 vehicles per day. During every 15-minute period over the week that MassDOT gathered data, the highest traffic volume was 585 vehicles, or a car approximately every six seconds. This is less than half of the roadway’s capacity, and at most times of day it operates at significantly lower volumes.
In regard to the merge distance and sight lines, MassDOT is correct that this merge is not optimal, but it is no worse than many other merges in use across the Commonwealth. The most pertinent of these may be the ramp from Massachusetts Avenue to the Turnpike opposite Newbury Street. That ramp has a similar grade to the Silver Line ramp and similarly poor sight lines, but the merge area at its base is far shorter than the Silver Line’s ramp. It’s just 200 feet from the end of the curb to the end of the merge area, while the Silver Line ramp has this much level space before the merge even begins. The roadway the ramp from Mass Avenue merges in to is both a faster roadway than the Ted Williams Tunnel and one with much more traffic than the HOV lane, yet MassPort’s Back Bay Logan Express buses use it every 20 minutes without incident.
This merge into the Ted Willians Tunnel, according to MassDOT, is too dangerous to use …
… but this merge from Massachusetts Avenue on to the Turnpike? Totally fine.
MassDOT: “Lastly, this ramp is utilized by law enforcement and first responders, as well as MassDOT emergency maintenance personnel and response teams. During emergency situations, it would not be feasible to coordinate immediate detours and closures to this ramp for bus service, which could further compound existing safety concerns while also hindering emergency operations and response efforts.”
This is a complete red herring. If an emergency response team needed to access the tunnel, they could do so. There’s only a bus every four minutes. And if there were a police car with a siren, the bus could wait for the police car to go first. That’s not hard. To think that it’s impossible for two state agencies to develop and implement contingency plans for emergencies is risible. If there was some sort of emergency situation that would require the ramp be closed to buses, it would be quite simple to coordinate detours for the Silver Line. The buses could use the loop-the-loop route they use today.The Commonwealth has invested nearly $100 million dollars in building the Silver Line Gateway project to provide better connectivity between Chelsea and Boston. The route promises a 19 minute travel time from Chelsea to the Seaport, so the 2 minute detour (at best; when traffic is heavy it can take 15 or 20 minutes) because of MassDOT’s obstinacy adds 10 percent to the travel time—and operating cost—to the route, negating many of the benefits we’ve invested in. With this project nearing completion and internecine interagency squabbling, it’s time to say: Mr. Baker, Ms. Pollack, Mr. Ramirez, tear down this (completely imaginary) wall.
Ari Ofsevit is a member of TransitMatters and a graduate student at MIT.