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Removing Motorists From Central Park Will Ease Traffic Congestion

Analysis of Central Park Drives Alternate Use Study

After hearing two presentations by the Department of Transportation (DOT) explaining their findings from the Central Park Drives Alternate Use Study we knew there had to be more to the story. The DOT's report to the community boards seemed to be scare tactics, showing the intersections experiencing heavy traffic flow. Increased traffic congestion is the main sticking point of those opposed to an Auto-Free Central Park, and rightfully so. By looking closely at the DOT's own data, closing the Central Park loop drives to autos will actually improve traffic flow.

I, on behalf of Transportation Alternatives (TA), obtained and analyzed the traffic data the DOT used to produce their report. We compared Scenario 1(the existing conditions) with Scenario 2 (closing the Central Park loop road) and noted the differences between the two. From the data, we found several positive results.

No Dire Consequences
The DOT found 6 intersection approaches will operate at a level of service F, which is the worst traffic rating possible. Considering the DOT studied 132 approaches and there are 1,470 intersection approaches in the study area, 6 is not much.

Traffic Volume Reduced
The number of vehicles counted in the study area decreases if the loop road is closed to them. In the morning peak-hour, the traffic volume shrinks by 4%. The evening peak-hour shows a 3% reduction. These trips are projected to move outside the study area.

No Significant Change in Average Volume/Capacity Ratio
Comparing the average volume/capacity ratio in the morning, Scenario 1 is at .591, while Scenario 2 is .596. The evening rush v/c ratio is .597 in Scenario 1, and .599 in Scenario 2. Volume/Capacity ratio is used to measure the ease of traffic flow in an intersection. Volume/Capacity ratio is determined by dividing the volume of traffic moving through an intersection by the number of vehicles that can move through the intersection. For example, .022 is smooth flowing and .953 is congested.

Majority of Intersections Unscathed
The v/c ratio doesn't change or is improved in over half of the intersections. In fact, 13 intersections show major traffic flow improvements.

Traffic Displaced to Locations That Can Handle It
Intersections with high volume/capacity ratios get small increases in traffic. The intersections that get major increases in traffic now have low volume/capacity ratios.

Flaws in Study

Shrinkage Not Factored In
The DOT assumed that all motorists that used Central Park's roadways would continue to drive if the roadways were closed. This is patently false. Reducing roadway capacity significantly reduces the number of people driving. The collapse of the West Side Highway provides a fine example of this phenomenon. People end up taking alternate means of transport as it becomes harder to drive.

Proper Education Necessary
This study envisioned many people driving all the way to the park and then realizing that it was closed to them, an absurd hypothesis. Drivers' choice of routes are easily changeable.

The Study Only Examined Motor Vehicle Behavior
We need to understand not only the routes which displaced motorists will take, but which modes they switch to. In addition we need to know what effects less cars will have on the modal choices of non-motorists. The study must examine the number of persons using every mode of transportation.

Critical Intersections Left Out
The intersection approaches at 7 Av and Central Park South are not examined. These intersections have been observed by us operating at Level of Service F in the AM peak hour, so removing traffic from Central Park will eliminate traffic problems there.

In addition, Times and Herald Squares were not studied. Since no cars will be coming out of Central Park onto 7 Av or heading for the park on 6 Av, traffic flow in these critical intersections will improve.

Volumes Not Reduced Where They Should Have Been
The DOT did not reduce traffic in many intersections even though closing the park would do so. The study showed all exits from the park loop road as having traffic on them. Intersections leading to and from the loop drive show no decrease in traffic.

Capacity Not Increased Where It Should Have Been
Since no cars are moving into and out of the park, it is easier for vehicles not going to the park to get through the intersection. The study made no point of this.

Corrections

To paint a more accurate picture of what would happen when cars are kicked out of Central Park, we corrected the errors made by the DOT, creating Scenario 2.TA. These remedial measures are modest and arose from discussion with the DOT staffmember who is performing their analysis.

These corrections still do not take into account the significant shrinkage that will take place if the loop roads are closed.

Examining the corrected data reveals Auto-Free Central Park will improve the overall traffic flow. The following findings are improvements and additions to those discussed for Scenario 2.

Traffic Volume Reduced
In the AM peak-hour, traffic in the study area decreases by 6%. The traffic volume in the PM peak-hour is reduced by 5%.

Traffic Flow Improved
The current level of service in the morning rush is .591, and will become .575 under Scenario 2.TA, a 3% improvement. In the evening, the level of service improves by 4%, dropping from .597 to .575. In both the AM and PM peak periods, thirty intersections show major traffic flow improvements. Traffic on all streets leading to and from the park loop road show reductions in traffic.

Conclusion

Not only has the DOT study demonstrated that traffic congestion will not be negatively impacted by permanently opening Central Park's loop road to park users, the research goes on to show this policy shift is likely to improve the traffic situation.


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Last updated: 4 April 1999