Traffic benefit ratio

Traffic benefit ratio (TBR) ratio of the number of load applications necessary to reach a specific failure state in a geosynthetic-reinforced pavement to the number of load applications required to reach the same failure state in an unreinforced section (ie, the same pavement section but without reinforcement). 

Step 4. Define reinforcement benefits in terms of Traffic Benefit Ratio (TBR) or Base Course Reduction Factor (BCR) Requires review of successful applications, field studies, and lab test results. 

The cost-benefit analysis including behavioural adaptation therefore included three types of benefit (1) accident reduction, (2) travel time saving, and (3) new trips in darkness. In the cost-benefit analysis not including behavioural adaptation, accident reduction was the only benefit. Figure 20.1 shows the estimated benefit-cost ratio of providing road lighting as a function of traffic volume in the two analyses. 

Many of the treatments have benefits other than safety (e.g., traffic flow) and the safety B/C ratio is therefore only one component of the benefits to be achieved. This, for example, was probably the case in the (expensive) construction of bypass roads in Norway and Sweden. 

The Utah DOT Traffic and Safety unit prepares Operational Safety Reports for certain resurfacing projects. These safety reports recommend safety improvements and provide the benefit/cost ratio associated with implementation. 

In New Zealand, the government not only required positive benefit-cost ratios before a project could proceed, but also mandated that the economic returns must reach a prescribed positive level. When this policy was introduced, safety projects became uncompetitive. The traffic safety specialists made a successful case for a switch from the direct cost method to the willingness-to-pay method for estimating the dollar value of a statistical life. The switch resulted in an approximate doubling of the value of a life and got a lot more safety projects over the line in the benefit-cost competition. Sadly, traffic safety advocates in New Zealand currently bemoan a failure to adequately adjust overtime, the values derived of this paradigm shift of well over a decade ago. ... 

---