Where is the world’s largest oil reserve? Venezuela? Saudi Arabia? Iran? Canada, or perhaps the United States? You’re getting warmer: it has been said that the biggest oil reservoir in the world is in the empty seats of American cars. The average occupancy rate is 1.1 for work trips, which accounts for 28 percent of household vehicle miles, and 1.6 overall. This translates into 10 trillion empty seat-miles annually. Thus far, the solution has been to cram more people into fewer vehicles. The Parkway City model addresses both carpooling and transit, but the real gains will be realized when we right-size vehicles to their use.
Our current road network is a one-size-fits-all grid of arterial roads and freeways which has to accommodate freight and light-duty vehicles (LDVs). Americans have also adopted a one-size-fits-all mentality when it comes to their cars. They would rather have a one-size, multi-purpose vehicle for all their needs, especially if they have to do battle on the freeway with 18-wheelers.
This attitude has suited the manufacturer quite well. Low fuel prices have led to an arms race in terms of vehicle size and power, as you can see from the graph below. The mantra, What’s good for GM is good for America kept fuel prices low and sales of full-size vehicles high even as energy reserves dwindled. Instead of seeing the obvious and gradually transitioning away from gas-guzzlers, we chose to drive straight into the wall of high prices. This wasn’t good for GM, and it wasn’t good for America.
The Parkway City Solution
What type of impact would right-sizing vehicles have? Separating light duty vehicle use from freight use can significantly reduce vehicle weight and increase the range of electric vehicles (EVs). A weight reduction of just 10 percent results in fuel savings of 7 percent. Cut weight, cut consumption, it is that simple.
It’s simple, but is it feasible? In a design experiment, Lotus Engineering was able to cut the weight of a mass-market utility vehicle by 38 percent using lighter materials and more efficient design. This cost just $1000 per vehicle and would take the average mid-size car from 2800 pounds to 2000. Going a step further, if the fleet were transitioned to compact and subcompact sizes, we could reduce the average 2800 pound weight to just 1400 pounds for a 35 percent reduction in energy use.
But that’s dangerous, right? A 1400 pound car on the road with an 80,000 pound tractor trailer is hazardous; the Parkway Grid, however, utilizes a maximum vehicle size (light truck or minibus) for parkways. Freight, and the heavy trucks used to haul it, would be restricted to main streets and freeways.
Turning to the Bikeway Grid: these paths would allow single-occupancy vehicles, ranging from ultra-light bicycles and scooters to fully-enclosed buggies weighing less than 500 pounds, with a maximum speed limit of 20 miles per hour. If the average vehicle here is 280 pounds, it would result in a 70 percent energy reduction versus a current midsize car.
The Parkway City also enhances the viability of Plug-In Hybrid Electric Vehicles (PHEV); because most light duty vehicles drive relatively short distances on most days, a PHEV with 40 miles of electric range can electrify 60 percent of miles driven. Even those with a 10-mile range could electrify 20 percent of miles driven.
The Parkway City strategy is in direct opposition to current thought: instead of trying to stuff more people into each vehicle, as transit does, this system slashes empty seats. If the average ridership is 1.5 persons per vehicle, and the average car has four seats, this means there are 2.5 empty seats per trip. 10 trillion empty-seat miles per year, collectively. Under the Parkway model:
- 40 percent of all miles could be driven by 1400 pound vehicles, which are 20 percent more efficient than 2000 pound vehicles.
- 20 percent of all miles could be driven by 280 pound vehicles, which are 50 percent more efficient than 2000 pound vehicles.
A greater mix of compact and subcompact vehicles would result in an 8 percent reduction in energy consumption. Ultra-light vehicles would cut another 10 percent. Light duty vehicles account for 60 percent of transportation energy use; this 18 percent reduction would create a total transportation consumption reduction of over 10 percent.
When athletes prepare for a fight, they cut weight. We, too, are in for a fight, and cutting weight is one way we can be ready to do battle on fossil fuel dependence, waste, and inefficiency.