AVs can help us reduce spending for road, bridge, and highway expansions. Here’s how.

By Rutt Bridges, forthcoming, 2017

In 2014, federal, state, and local spending on highways was $165 billion.1 Capital spending for new highways, rehabilitation of existing roads, and new equipment consumed 56%, or $92.4 billion. The remaining $72.6 billion went for operations and maintenance. State and local government provided 72% of the total funding.2

Savings due to reduced road repairs: FreeRide Carpools and for-hire SAVs are only on the road when requested, while buses must make their scheduled rounds regardless of demand. But more importantly, transit-on-demand SAV-2s will weigh 2,300 pounds with 2-passengers (see Appendix XI) and SAV-4s will weigh 3,500 pounds with 3-passengers (see Appendix IX), for an average of 2,900 pounds per vehicle. Two‐axle 40‐foot buses comprise approximately two‐thirds of the transit bus fleet in the United States. The average 44-seat, 40-foot bus weighs 32,520 pounds empty and close to 40,000 pounds with the seats all full.3

Why does this matter? Unfortunately, based on testing by the American Association of State Highway and Transportation Officials, road damage rises with the fourth power of the weight load on each axle.4 Therefore, the contribution of passenger cars to road damage is negligible compared to the big rigs.5 Almost all road damage is caused by heavier vehicles such as trucks and buses. Eliminating heavy buses on urban and suburban roads will result in a meaningful reduction in road damage. Fewer road repairs means less congestion as well as less expense.

There will still be plenty of 80,000-pound, five-axle 18-wheelers, the big kahunas of highway damage, that cause thousands of times as much harm as the average SUV. Therefore, we will estimate a modest 5% reduction in the $165 billion total budget due to the removal of buses, for a savings of $8 billion.

Savings due to reduced road and highway expansions: The 2027 Rush-hour Vehicle Model includes a 32.2% reduction in total commuting vehicles (see Chapter 11, Table 11.1). However, the estimated growth of commuter vehicles based on the recent growth of passenger miles traveled is 16.6%. That is 15.6% less than the reduction due to ridesharing driverless FreeRide Carpools and for-hire SAVs. Combined with the increased highway carrying capacity resulting from SAV Platoon Lanes and other benefits we have discussed, there should be few expansions needed to our current infrastructure.

In most cities, road and highway expansion and rehabilitation projects are often carried out in response to rush-hour congestion. While it still costs a lot to maintain the existing infrastructure, if we can conquer congestion through the ideas presented in this book, we should be able to save at least a third of the $165 billion we currently spend. That would mean a reduction of another $55 billion. Adding in the $8 billion savings on road damage due to buses, we get total savings of $63 billion.

Required infrastructure changes for driverless vehicles: Some vendors have driverless designs that require major modifications to our roads and highways. However, there are successful competitors, such as Google, that don’t require any significant changes. If you need lots of government help, good luck. Governments don’t move quickly, and they can’t reallocate budgets without seemingly endless public hearings and committee meetings. Strategies that avoid putting financial burdens on government will leave their competitors in the dust.

Driverless technology is advancing at a breakneck pace. Unless you want to be late to the party, rethink your problem and solve it yourself. Our highways are already paved with enough flat squirrels that couldn’t make a decision. Don’t be a flat squirrel.

The one exception to this is the need to provide Internet access to all citizens, rural, urban, or suburban, regardless of their economic means. Not being connected is already severely limiting educational and employment opportunities. This disadvantage is growing every day. Emerging technologies, such as 5G wireless,6 WiGig,7 and the new White-Fi8 (offering a potential range of several miles for rural areas), will make it possible to provide free Internet to everyone, though perhaps with some advertising. Many roads and highways increasingly include fiber along their right-of-ways, making them the perfect backbone for delivery of these services. This backbone will be more and more valuable to everyone as Internet of Things9 (IoT) devices become pervasive.

How to fix transportation funding: The question of fuel taxes, transportation’s primary source of funding, is an ever-increasing concern. Due to existing CAFE (Corporate Average Fuel Economy) standards, conventional vehicles are paying less and less in fuel taxes. Meanwhile, cheaper batteries, longer range, and lower maintenance electric vehicles will continue to capture greater market share. Even if FreeRide Carpools and for-hire SAVs substantially reduce the need for highway expansions, we’ll still need to maintain our highways, bridges, and roads. Electric vehicles will need to carry part of that burden. How should they be taxed?


A mileage tax seems to be the only practical answer. GPS data combined with advanced digital odometers will make it relatively straightforward to wirelessly report state-by-state monthly total miles-traveled without reporting the driver’s every move.


How much per mile? Today’s average conventional light passenger vehicle gets 23.2 miles per gallon,10 The average U.S. state plus federal gasoline tax as of February 2017 was 49.44 cents per gallon,11 so on average gasoline taxes currently cost 2.13 cents per mile. However, the average weight for vehicles produced in model year 2015 was 4,035 pounds.12 By comparison, the average of the weights of the proposed SAV-2 and SAV-4 (see Appendix IX and Appendix XI) is 2,665 pounds, or only 66% as much. Since weight determines the road damage caused by a vehicle, reducing the 2.13 cents per mile proportionally by the weight 0.66 difference suggests a 1.4 cents per mile tax for the SAVs. This also agrees with the recommended mileage tax in Chapter 3, Why Electric.


The actual mileage tax rate with vary across the U.S. since state fuel taxes vary quite a bit. Both mileage taxes and fuel taxes should also be annually adjusted for inflation to stabilize tax revenue over time. However, as this book demonstrates, ridesharing provides enormous financial and environmental benefits both to government and individuals. Politicians should consider exempting electric vehicles that provide free rush hour ridesharing services in partnership with transit agencies.


At the other extreme, there should be a steep mileage tax to discourage empty driverless cars from circling the block while their owners shop or run errands. Efficient multi-parcel delivery vehicles that reduce empty miles by discouraging people from sending their driverless cars on errands might also be tax-exempt.


Human-powered bike and trike deliveries also have a valuable role to play, especially for apartments and limited-access destinations. Laundry, groceries, and hot pizzas can be transported by lightweight special-purpose vehicles, some traveling on sidewalks, that text you to arrange verified drop-offs and again just as they are arriving at your door. Pizza hijackers will be photographed, chased down, and turned into police. Defensive skunk-sprays will be permitted, but robotic stun-guns and laser cannons will be strictly prohibited.


Despite inflation, growing congestion, and improving EPA mileage ratings, the federal gas tax has been fixed at 18.4 cents since 1993.13 Since 2000, transportation spending has exceeded revenue sources in all but two years.14 The Federal Highway Trust Fund has been spent down and continues to be propped up by transfers from the U.S. Treasury’s General Fund.


Meanwhile, it is widely recognized that maintenance of America’s transportation infrastructure has been sorely neglected. Our standing for the quality of our roads fell from 8th in the world in 2008 to 16th by 2014, just six short years.15 There will also be some necessary spending to create new eight or nine feet wide SAV Platoon Lanes and add passenger pickup/drop-off zones within cities and near mass transit stations. These costs are real, but are dwarfed by what we would need to spend to compensate for conventional lane additions to address our growing congestion challenges. Rather than claim the savings from SAVs, we should reinvest these funds to make our existing roads, bridges, and highways safer for everyone.


In a 2016 study, the AAA estimated the cost of potholes to drivers at $3 billion a year.16 By 2027, SAVs will be able to help by providing repair crews with the maps and the pothole volume estimates needed to get the job done. But those repair crews’ salaries must come from somewhere.

While SAV Carpools may make it possible to avoid increasing the federal fuels tax, at a minimum a mileage tax on electric vehicles should be implemented and both the mileage tax and the fuels tax should be indexed to inflation. Everyone should pay to play, and the money we collect for maintaining our transportation infrastructure should never diverted to other well-intended causes.


  1. Public Spending on Transportation and Water Infrastructure, 1956 to 2014,” Congressional Budget Office, Exhibit 1, p. 8.
  2. Ibid, Exhibit 18, p. 28.
  3. An Analysis of Transit Bus Axle Weight Issues,” MORR Transportation Consulting Ltd., November 2014, Table 7, p. 25.
  4. Generalized Fourth Power Law,” Pavement Interactive, Equivalent Single Axle Load.
  5. Pavement Engineering Considerations,” California DOT, Division of Designs, Highway Designs Manual.
  6. David Talbot, “5G Wireless Is Coming, and It’s Going to Blow You Away,” MIT Technology Review, July 27, 2016.
  7. Tom Simonite, “Facebook is Testing a Super-Speed Public Wi-Fi System,” MIT Technology Review, April 13, 2016.
  8. Mark Barrett, “The Future of Wi-Fi Revealed,” Electronic Design, September 27, 2016.
  9. Internet of Things,” Wikipedia.
  10. Table 4-23, Average Fuel Efficiency of U.S. Light Duty Vehicles, 2014,” U.S. DOT, Bureau of Transportation Statistics.
  11. Gasoline Tax,” American Petroleum Institute, 2016.
  12. Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends Report Overview,” Environmental Protection Agency, 1975-2016.
  13. Sarah K. Urahn, “Intergovernmental Challenges in Surface Transportation Funding,” The Pew Charitable Trusts, September 2014, p. 2.
  14. Ibid, p. 11.
  15. The Blue Paper,” S. Department of Transportation.
  16. Pothole Damage Costs U.S. Drivers $3 Billion Annually,” AAA, February 17, 2016.