PennDOT Nixes Parkway East Ramp Closing Plan

PennDOT Nixes Parkway East Ramp Closing Plan

Congratulations to PennDOT. It has wisely and prudently decided not to go ahead with a scheme to close two westbound ramps on the Parkway East during rush hours. 

 

 

The plan was based on a University of Pittsburgh study that examined possible ways to improve flow through the Parkway East corridor. 

 

Three options were evaluated. The proposal to close the Ardmore Boulevard and Braddock Avenue westbound ramps showed the greatest improvement in traffic flow and reduction of travel time. At the peak rush hour traffic period the study group found an estimated time savings of five minutes for the morning Parkway trip. Unfortunately, the study failed to answer many of the questions about what would happen to traffic on surface streets as Parkway users entering at Ardmore Boulevard and Braddock Avenue were forced to find other ways to Oakland, Downtown or other points west.  They did recommend a number of street changes to improve traffic flow in the affected area but it is not at all clear what the added traffic would do to congestion patterns or travel times  and possible impacts on local residents headed to schools or to work inside the affected areas.

 

In all likelihood there are many drivers from outside the affected area who are already using routes on surface streets to avoid the Parkway backups. Adding more traffic to those streets would certainly not be advisable.

 

The greater point is that saving five minutes per day for drivers coming from Churchill or Murrysville does not appear to be an adequate benefit to balance against the additional travel times and congestion problems likely to be created on  the surface streets.  The question arises; why should people living closer to the City be inconvenienced significantly so commuters from farther out can save five minutes?  Moreover, if commuters from farther out are saving five minutes will that encourage more to get on the Parkway at rush hour to the point that eventually the five minute savings is eliminated?  Except that the new rush hour flow would have replaced the Ardmore and Braddock ramp users.

 

No one doubts that Parkway traffic is bad and frustrating at rush hour.  The system was designed for traffic flows much lower than the road is being tasked to carry. Then too, there is the decades long bottleneck issue-the Squirrel Hill Tunnel. The two tunnel lanes of traffic can only hope to accommodate 3,600 to 4,000 cars per hour safely. And this assumes there are no other bottlenecks downstream from the tunnel sufficient to slow the exit of traffic from the tunnel-that is, traffic is free flowing after the tunnel. If well above 4,000 cars per hour are trying to get through the tunnel at the rush hour peak, there will inevitably be a backup and the queue of cars will get longer the longer the peak demand lasts. Widening the approaching road to three lanes is not an effective option since all the traffic has to slow to allow merging and the two lane limit of capacity will control throughput.

 

As long as the tunnel is setting the limit to the number of vehicles per hour transiting the Parkway East to the Oakland and Downtown exits, all traffic engineers can do is work to insure that traffic maintains a good speed entering the tunnel so that braking doesn’t create a chain reaction causing traffic to come to a full stop. As long as speed can be maintained above a minimal level entering and moving through the tunnel, throughput can be sustained at capacity levels.  There is not much else that can be done.  No one has seriously suggested adding lanes to the tunnel or finding a way to add lanes that bypass the tunnel. 

 

There are alternative approaches to reduce the long transit times that impose costs on the commuters in terms of time spent on the road. First, get permission to levy a toll on users of the Parkway during rush hour to encourage drivers to leave before or after the peak travel times. That will probably require Federal legislation and would not be popular with many drivers, although for the convenience of a faster commute there might be some drivers who would gladly pay a peak hour toll.

 

Second, develop light rail or faster express buses to move people from points east into Oakland or Downtown. It is too bad that over half of a billion dollars was spent on the North Shore Connector that could have been far better used to build several miles of busway or light rail. Many will deride the idea, but if the eastern suburbs and towns further east are going to add Parkway using commuters in future years as has happened over the past, the crowded situation on the Parkway will get worse.  At some point, the travel time will reach a point that it will deter any further growth of commuters that rely on the Parkway.