Livability proponents celebrate that car-centric Level of Service (LOS) is finally on its way out, at least in California.Wouldn’t it be great if there was a similar bike- or walk-centric metric that could be used instead? UCLA Lewis Center and Institute for Transportation Studies researchers have studied some of the published metrics for evaluating how well streets serve pedestrians and cyclists. The researchers’ conclusion: in all of the bike and ped metrics they reviewed, there is no silver bullet. Moreover, adapting LOS doesn’t look like a fruitful approach.
Level of Service is a standard, simplistic engineering measure that uses car throughput to assign streets a letter grade from A to F. For nearly 60 years, LOS has been the predominant way that planners and engineers quantify streets. LOS guides policy and investment, justifying making streets wider and more car-centric. Because LOS only considers cars, LOS justifies widening roadways, adding turn lanes, and other so-called improvements that degrade conditions for people using bikes, their feet, or transit. To remedy this, transportation professionals have created new metrics designed to grade other modes. These include Pedestrian Level of Service (PLOS) and Bicycle Level of Service (BLOS), both of which are components of Multi-Modal Level of Service (MMLOS.)
There are some inherent problems with adapting a car-centric measure like LOS to bicycling and walking. Where people driving tend to see other cars as obstacles, pedestrians often prefer to walk where other people are out walking. Cyclists experience a safety in numbers effect, where LOS tends to just find congestion in numbers.
Though there are now many metrics from various parts of the world, UCLA researchers Madeline Brozen and Herbie Huff focused primarily on the following three metrics:
- Multi-Modal Level of Service, included in the 2010 Highway Capacity Manual (HCM), the official federal evaluation tool developed by the Transportation Research Board of the National Academy of Sciences
- Bicycle and Pedestrian Environmental Quality Index (BEQI and PEQI), developed by the San Francisco Department of Public Health
- Urban Street Design Guidelines performance measures, developed by the city of Charlotte, North Carolina
Huff and Brozen used these tools to score sections of streets in the city of Santa Monica. They subsequently evaluated the sensitivity of the tools by comparing scores for existing condition to scores for potential improvements, including bike lanes, road diets, medians, etc.
In comparing existing sites to multiple potential improvements, the models showed “little variation,” with none of the improvements appearing ideal or raising the score to an “A.” Therefore, the models were ineffective for deciding between potential designs. Read more…