by jmarandino » Thu Sep 08, 2011 9:42 am
Here in Southern New Jersey, I've prepared a Benefit-Cost Analysis using the HSM for a existing four-legged, signalized intersection for purposes of obtain federal safety money through HSIP. Countermeasures included adding protected/permissive phasing for existing left-turn lanes on all four approaches where only permissive phasing was orginally in place as well as changing the clearance intervals to coincide with ITE recommendations.
I took advantage of the Excel spreadsheets provided on the HSM website for the Predictive Method (urban and suburban intersection), applied the EB Method (hopefully correctly). From the Predictive Method results I recreated Sample Problem 7.9 within the Highway Safety Manual (Chapter 7 Economic Appraisal) and calculated a Benefit-Cost Ration of 5.6, showing the project is cost-effective based upon the change in crash frequency.
I intended to run the same predictive method analysis using HiSafe, but was having trouble with the application of the EB Method.
I will be giving a presenation on the project at the MASITE Annual Conference in Cape May, September 19th.