Congestion Perception Perhaps Congested
Guest Correspondence
SRQ DAILY
SATURDAY JAN 24, 2015 |
BY KEVIN COOPER
Roadway performance evaluation is far more technical than how long one thinks it should take to get to their local grocery store versus how long it actually takes. The term used to evaluate and discuss performance is known as ‘Level Of Service.’ The roadway LOS, according to the County’s Access Management Technical Manual, is defined as “a qualitative measure describing operational conditions within a traffic stream. Level of service is based on factors such as speed and travel time, freedom to maneuver, traffic interruptions, comfort and convenience, and safety.”
It’s important to note there are a number of things that affect the LOS rating aside from number of vehicles on the roadway. The number of intersections, types of intersections (e.g., signalized or signed), signalization patterns, type of vehicles, roadway width and distance between the edge of lanes and the curb can all have a direct impact. Roadway LOS is graded on a letter scale from ‘A’ to ‘F.’ This scale, however, can be somewhat misleading in our culture because an ‘A’ in this case, while it might be considered the best, is relatively undesirable for a community. If a roadway has an ‘A’ LOS, it’s likely few people need or want to travel the roadway or that the roadway is severely overbuilt. In the overbuilt scenario, picture a standard two-lane roadway being expanded to eight lanes. That would likely allow the roadway to attain an ‘A’ rating, but would anyone actually advocate for it? Most County roadways have a minimum adopted service standard of ‘C,’ but even that is a relatively high threshold. By industry standards, drivers on a ‘C’ roadway would expect to see a minimum vehicle spacing of about 11 car lengths. For perspective, that distance is about the same as the height of the Golden Gate Bridge... between each vehicle.
Some in the Sarasota community have the perception traffic is getting worse and elected officials have failed to properly plan for increases in population and development. Lost in the conversation seems to be a technical review of how Sarasota’s roadways actually perform from a data-driven, statistical standpoint. A review of the County’s most recent (2013) generalized LOS analysis might paint a surprising picture for those that perceive Sarasota County as being overrun by development and gridlock. The review would show that while there 38 roadway segments are technically failing, 36 roadway segments throughout the County performed at an ‘A’ level. Perhaps most importantly, nearly two-thirds of the 465 roadway segments analyzed were performing at an LOS of ‘C’ or better. In fact, Sarasota County had more combined ‘A’- and ‘B’-rated roadway segments than it did ‘D’, ‘E’ and ‘F’ segments combined.
One should understand the LOS rating is based on a measure known as design hourly volume, which, in this case, is the four highest, contiguous 15-minute traffic counts within a peak travel time (e.g., 4-6pm). Basically, the rating is based on the currently reasonable worst case scenario. It’s also worth noting the average length of an analyzed “segment” is less than a mile. So a segment of a roadway may be “failing” but that doesn’t mean the entire roadway is.
It’s also important to understand how the roadway system’s performance has changed over time. When comparing the 2013 LOS analysis to the 2006 analysis, one can get a picture of the direction roadway performance has been trending over the past several years. Of the 428 roadway segments analyzed in both 2006 and 2013, 110 (25.7 percent) were performing at a higher LOS in 2013 than in 2006, and 302 (70.6 percent) were performing at the same LOS (of which 264 were performing at a ‘D’ or better). Only 16 (3.7 percent) segments were actually performing worse in 2013 than 2006.
During a recent meeting, the Sarasota Board of County Commissioners seemed almost taken aback. One commissioner asked Jonathan Paul, a transportation planning consultant with graduate degrees in both public administration and urban planning, to repeat himself. Paul reiterated, “Sarasota County has done a great job in terms of keeping up with its roadway infrastructure, and ensuring development is accommodated by transportation infrastructure. They’ve been implementing (traffic) concurrency better than most communities I’ve seen across the state of Florida.”
Immediately following, another Commissioner perhaps jokingly requested, “One more time.” “Maybe it’ll actually get printed,” said another. “Don’t count on it,” stated a third.
Why? It certainly bears repeating.
SRQ Daily Columnist Kevin Cooper is the vice president for Public Policy and Sarasota Tomorrow Initiatives for The Greater Sarasota Chamber of Commerce
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