Estimating the Energy Consumption Impact of Casual Carpooling
1.2. Objective of the Paper
2. Literature and Research
2.1. Casual Carpooling
|Location||Morning Pick-up Pts||After-noon Pick-up Pts||Average Daily Car-pools Per Pick-up Point||Participants Per Day (Year of Last Report)||Extent of Payment by Riders|
|Washing-ton, DC||24||16||134||9689 (2006)||Nil|
|San Francis-co, CA||22||1||approx. 150||8000–10,000 (1999)|
|Some riders on some routes pay $1.00 or $1.25 towards cost of discounted bridge toll since July 2010|
|Houston, TX||3||1||100||approx. 900 (2007)||Nil|
2.2. Transportation Energy Consumption Calculations
3. Analysis: Energy Impact of Casual Carpooling
- In 3.1 the energy use is estimated for casual carpoolers in a single casual carpooling route, compared with a mixture of bus riding and SOV driving.
- In 3.2 a simple model is created for estimating the impact of casual carpooling on other traffic in the same corridor, and
- In 3.3 the simple model is used to estimate the total impact of casual carpooling in San Francisco.
3.1. Comparing the Energy Use of a Single Casual Carpooling Route with a Bus/SOV Alternative
3.1.1. A Hypothetical Case with 600 Participants Daily (200 Three-Person Carpools)
- Three 55-seat buses will be used. (Some may argue that San Francisco commuters would switch to Bay Area Rapid Transit (BART) trains rather than to buses. It is noted that this could be correct, however there are capacity constraints on BART as described in Consider Congestion Pricing for BART, , and while individual passengers would probably be able to make the change, a wholesale switch from casual carpooling would probably swamp the system. Further, whether three 55 seat buses would be used, or some other configuration of bus size and frequency, would be a management decision for the operator. A different configuration would deliver a different energy consumption answer).
- Table 2 shows a potential trip pattern.
- Buses deadhead (return empty) three times each in order to carry the full number of passengers, achieving an average load factor of 44.4%.
- Buses use 15.0 MJ/km .
- The casual carpools use the HOV lane and travel at the average speed for the East Bay HOV lanes, 90 km/h, while
- The SOVs travel in the East Bay general purpose lanes at 38.5 km/h.
|Departure||Bus 1||Bus 2||Bus 3||Cumulative|
|Trips per Bus||3||3||3||9|
|Distance per Round Trip||44.8|
|Total km bus travel||403.2|
|MJ/km for bus||15|
|Casual Carpools Fuel Use|
3.2. A Simple Model for Estimating the Impact of Reduced Traffic on Fuel Consumption
3.3. Estimating the Total Impact of Casual Carpooling
- With existing casual carpooling, and
- If casual carpooling ceased to operate from all locations, participants switching mode according to the survey findings reported by .
|Factor||Volume||Value||Total $US Million per Annum|
|Energy (million liters gasoline||1.7–3.5||$3.00||1.35–2.7|
|Emissions (tonnes CO2e)||4100–8200||$15||0.05–0.1|
|Time Savings for all Commuters||900,000 hours||$30||27.0|
|Buses not purchased||45 buses||$0.5 million @10% per annum||2.20|
|Bus Operating Costs not incurred||45 drivers||$50,000 pa||2.20|
|Total per annum||>30.0|
4. Discussion and Conclusions
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Minett, P.; Pearce, J. Estimating the Energy Consumption Impact of Casual Carpooling. Energies 2011, 4, 126-139. https://doi.org/10.3390/en4010126
Minett P, Pearce J. Estimating the Energy Consumption Impact of Casual Carpooling. Energies. 2011; 4(1):126-139. https://doi.org/10.3390/en4010126Chicago/Turabian Style
Minett, Paul, and John Pearce. 2011. "Estimating the Energy Consumption Impact of Casual Carpooling" Energies 4, no. 1: 126-139. https://doi.org/10.3390/en4010126