Doc Drop: Fredericksburg Park Traffic Study

A proposed subdivision near the intersection of Lee Drive and Lafayette Boulevard has generated concerns about its impact on nearby traffic. To try and clear things up, the city of Fredericksburg commissioned a traffic study which evaluated the potential effects of , which would have two entrances; one located near the intersection of Lee and Lafayette, and a second on Alum Springs Road. 

The evaluation estimates that the subdivision will generate a total of 65 inbound and outbound vehicle trips during morning peak travel hours and 85 inbound and outbound trips during evening peak travel hours. Of those, 85 percent of the trips are predicted to use the Lafayette Boulevard access, the other 15 percent using Alum Springs Road access.

Estimated Traffic Generation for Fredericksburg Park:

The evaluation goes on to say that Alum Springs Road could experience some uptick in delays due to the additional traffic, but they are not expected to be significant. 

Traffic impact along Lafayette Boulevard is also predicted to be minimal. However, the study does say that delays could increase on Lee Drive as a result of the subdivision access point. 

The full copy of the city's evaluation of the impacts of the Fredericksburg Park/Telegraph Hill is included in this article for you to review. 

How Traffic Studies Work

Generally, traffic data is collected during peak hours and compared with transportation engineering industry standard data to find an analytic baseline with which to predict impacts on future traffic flow. It's called the Highway Capacity Method, which combines trip generation, choice of transport, choice of route and time of day when trips are made into data which can be used to forecast traffic flow. 

"Using engineering judgement, you look at the patterns of trip making, the magnitude of traffic generation and the ways in which people will travel through an intersection," said David White, Transportation Engineer with Kimley-Horn Associates, the firm which produced the Fredericksburg Park traffic evaluation. "It's a very practically minded and empirically based approach."

The source of their reference data is a set of information called Trip Generation published by the non-profit Institute of Transportation Engineers. For transportation engineers, it's something of a Bible. It contains nationally collected data on the expected amounts of traffic generation for any type of development.