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62 Separation of Vehicles--CMV-Only Lanes the analysis did not consider the negative environmental impacts of CMV-only lanes such as the noise impacts of concentrated truck traffic, due to inadequate information and methods for monetizing noise impacts (also, none of the available studies provided any data that could be used to support this analysis). 4.2.2 Private-Sector Benefits Private-sector benefits could include the following: Productivity benefits including productivity enhancements realized by trucks using the truck-only lanes, as a result of increased speeds as well as increased payloads in the case of LCV operations. Travel time savings and reliability benefits for trucks such that trucks diverting to truck-only lanes from the general purpose lanes will experience significant improvements in performance associated with improved travel speeds (travel time savings) and reliability benefits due to reduction in accidents as a result of more stable traffic flows and homogeneity of traffic on the truck-only lanes. Since the travel time savings benefits for trucks on the truck-only lanes are captured under the productivity benefits (due to increased speeds) above, these savings are not included under the travel time savings performance measure (to avoid double-counting benefits). Trucks choosing to remain on the general purpose lanes (i.e., trucks not diverting to the truck-only lanes) will have travel time savings and reliability benefits (due to conges- tion reduction on the general purpose lanes), which are included in the travel time savings and reliability performance measures. 4.3. Data Inputs for Monetization of Performance Metrics In order to compare benefits across benefit categories and to costs, the performance metrics had to be converted to a consistent unit of valuation. This involved monetizing the performance benefits to equivalent dollar values. In order to monetize benefits, the default factors in Table 4.1 were used. The values presented in Table 4.1 are for 2008 dollars (in the NPV analysis, these fac- Table 4.1. Default values for benefits monetization factors, indexed for 2008. Monetization Factor Default Value Source 1 Truck Value of Time ($ per Hour) 39 Average value (indexed to 2008) for heavy-heavy duty trucks (HHDT) derived from various sources (refer to Table C.1 in Appendix C) Auto Value of Time ($ per Hour) 10 Average value (indexed to 2008) based on the assumption that auto value of time is approximately 50% of average wage rate Fatality Accidents ($ per Accident) 4,365,164 FHWA2 Injury Accidents ($ per Accident) 131,642 FHWA2 Property-Damage-Only Accidents ($ per 8,226 FHWA2 Accident) Notes: 1. The auto and truck value of time estimates presented in the table are used to monetize travel time savings. For monetizing travel time reliability benefits (measured in terms of savings in incident-related delay), these estimates are adjusted by a factor of 1.5. 2. Federal Highway Administration, Crash Cost Estimates by Maximum Police-Reported Injury Severity Within Selected Crash Geometries, Publication No. FHWA-HRT-05-051, October 2005.