Development Type: Bank
Services Provided: Access Study
Client: HTG Architects
Access to a site is a key consideration for any development. In general, most businesses want more access to make it easier to get to their front door. Often, the site plan reflects a circulation pattern based on an assumption of several access points to the roadway system. On flip side, government agencies typically have standards and guidelines to maximize the flow and safety of their transportation networks. These guidelines can limit the number and type of access. Our traffic engineering expertise is frequently called upon to help determine the appropriate access for a site.
In the City of Golden Valley, Minnesota, HTG Architects approached Spack Consulting about an access case for a proposed bank, TruStone Financial. The site is bordered by local roads to the north and east with a busy state highway to the south. The proposed site plan rightly did not suggest direct access to the state highway, but showed full access to the northern local road and right in/right out access to the eastern local road. Citing proximity and potential impacts to the state highway intersection, the Minnesota Department of Transportation recommended no access to the eastern local road.
Spack Consulting’s task was to provide an independent evaluation of the eastern access and recommend allowing the right in/right out only or recommend eliminating the driveway from the site plan.
The state, the county, and the city all have access management guidelines, which generally provide a good start. In the absence of other information, we would typically reference the guidelines. For a specific case like this, we like to examine more in-depth information, including:
Following our review of these aspects of the proposed project and access, we recommended that a Right Out Only access be allowed with the access moved about 100 feet farther from the intersection with the state highway. This recommendation balanced the need for mobility and safety with the importance of access for the proposed bank. The crash risk was reduced by limiting movements and moving the access kept the driveway out of the 95th percentile queues (jargon alert – the point of vehicle stacking that is exceeded only five percent of the time; i.e. the vast majority of queues will be at or below that point).
As a side note, we also recommended that the state examine the signal timing at the intersection of the state highway and the local road. The signal timing used a 210-second cycle length during the peaks, with most time devoted to the state highway. A more moderate cycle length of 150 seconds could reduce the vehicle stacking on the local road, although overall impacts to the state highway system would need to be examined.
The City moved forward on the proposed bank with our recommendation for the limited Right Out Only access, which has been working well according to both sides of the initial argument.