Cost Benefit Analysis
We performed cost estimates for each of our alternatives. We included the costs of Roadway, Bridge, Right of Way, Design, Construction & Administration, and a 25% Contingency. We used unit prices and estimates from Caltrans cost estimates documents. All costs are in millions of dollars and are current year 2014 present value. The table below summarizes our final cost estimates.
In addition to cost estimates, we performed a benefit analysis for each alternative. We calculated the benefits of constructing a new interchange at Franklin Street and compared it to not constructing the new interchange. The entire study area, including Railroad Canyon Road Interchange, was included in the benefit analysis. We calculated the benefits of Total Vehicle Delay Saved, Total Vehicle Stops Saved, Fuel Use Reduced, CO2 Emissions Reduced, and Accessibility Benefit.
For accessibility benefit, we measured the travel time from an arbitrary location in a future residential area to access the I-15 at Railroad Canyon Road interchange. Then we measured the travel time from the same arbitrary location to access the I-15 if the new interchange at Franklin Street was constructed. The difference between these two travel times is our accessibility benefit. The following figures show the difference between the two travel times and the two distances.
The following chart shows the total vehicle delay, total vehicle stops, fuel use, and CO2 emissions for our entire study area. The red bar represents these values if Franklin Street interchange was not constructed. The green bar represents these values if Franklin Street interchange was constructed. The difference between these two scenarios is significant, and a new Franklin Street interchange greatly reduces the total vehicle delay, total vehicle stops, fuel use, and CO2 emissions. We can see that having a new Franklin Street interchange is extremely beneficial to the study area and to the City of Lake Elsinore.
Benefit (2020 - 2040)
The line graph shows the annual benefit of each year for each alternative from year 2020 to year 2040. The bar graph shows the total benefits for each alternative for the 20 year design life. All values are calculated in 2014 present value.
Total Benefit of 20 Year Design Life
With the cost and benefit calculated, we were able to find the Benefit/Cost Ratio. The following table summarizes our benefit/cost ratio calculations.
Weighted Decision Matrix
We performed a Weighted Decision Matrix to determine our recommended alternative. The categories we considered, listed in order of importance, are: local circulation, benefit, adaptability, pedestrian and bike friendly, cost, freeway operation, environmental impacts, right of way impacts, and ease of construction. We weighted each category, assigned a score using engineering judgment, and calculated a total score for each alternative. The Partial Clover alternative scored the highest at 294. We proceeded with the Partial Clover as our recommended alternative.