What happened to traffic?

Dateline: Minneapolis, November 4, 2030

Remember traffic? It was only 30 years ago that people were complaining about getting stuck in traffic. But traffic peaked in the early part of the Century, and has fallen ever since. A few observers picked this up early, but many transportation agencies were in denial. At the time, most analysts saw only two possible futures:

  • Future 1: Per capita vehicle travel resumes an upward path. This forecast was the proverbial ostrich with its sand-encased head.
  • Future 2: Per capita vehicle travel remains flat but traffic grows with population. Future 2 was already causing concerns as it created pressures on revenues (which were then dependent on falling gas tax revenue), yet DOTs still claimed needs for new construction and expansion of existing roadways despite overall falling demand. Some argued that though demand was falling on average, it wasn’t falling everywhere. And there were still unsolved problems that don’t go away just because travel isn’t increasing.
  • No one in power foresaw what actually happened.

  • Future 3: Per capita vehicle travel falls significantly. At first people attributed this to the Great Recession of the late Bush Presidency, but the evidence was that travel began dropping before the economy tanked. Technology restructured personal travel the way it completely devastated many other industries (remember newspapers, the post office, buying records and paper books, your land-line phone, canals, long distance passenger trains, broadcast television, electric utilities, going to College). Just look at this picture of demand for mail:


Why did traffic fall off a cliff?

Workers no longer “go” to work 6 days a week. Workers got Saturday off in the mid-20th Century. Getting every-other Friday off (the 5/4 schedule) became standard by 2015, establishing the 3-day weekend every other week as the norm. By 2020, this was every weekend, as people moved to a 9 hour day, 4 days per week at the office, and the other 4 hours were “at home” work – checking email on the long weekend, erasing once strict separation of home and work. By 2025 taking every-other Monday off (the 4/3 schedule) was established in most large employers. Today we are seeing half-days on Wednesdays for many office workers, with only Tuesdays, Wednesday, and Thursdays as interactive collaboration days. The “flipped” office, where people were expected to do “work” at home on their own computers, and only show up for meetings is now standard.

The empty office buildings across the landscape led to the famous Skyscraper Crash, the Real Estate Office – fueled recession of 2021. Many of those empty buildings were converted to apartments, as we had about twice as much office space as we needed with the new work arrangements. Some cities were virtually abandoned by business in this process. This helped undercut new residential construction in the suburbs, and suburban land prices fell, attracting lower income immigrants, who subdivided large tract mansions into housing for large extended families, and leading to a measurable “white-flight” back to the center city. So while the suburbs were now less expensive, some actually gained population. Lower income residents still own cars, but not as many, and many a 2 and 3-car garage is being transformed into a workshop or small store.

Shorter careers are also the norm now, almost half the population doesn’t enter the regular workforce until 30, and most leave by 60. The workforce has continued its drop as technology-enabled worker productivity reduces the value of older workers. Firms also are not interested in paying for training, so most people now go through a 10-year unpaid internship while simultaneously attending school online and engaging other pursuits on a more or less random schedule.

Shoppers no longer “go” to shop, but order online, or let ‘bots and virtual agents order for them, especially for regular stocks like paper towels, napkins, and Spam. And then they let most goods get delivered. With less window shopping and a decline in advertising, the culture became less materialistic, going shopping as activity continues its long 30 year drop, and consumption of material goods has declined with it. Internet Ad-blockers, Netflix, and other time-shifting technologies made ads decline (though not disappear, many companies now want to coat road surfaces with new digital ad-delivery technology – a proposal that is splitting the Coalition Government in a few states), and desperate DOTs are looking favorably on sponsored roads).

Widespread car-sharing programs made it possible for many people, especially in cities, to let go of ownership of their cars. Instead of having a very low marginal cost for a trip, now there is a higher cost per trip, making people think twice, and drive less.

More urban living, much of it in abandoned and remodeled office buildings, reduced the distances people needed to travel. Many 20-somethings live in these windowless, but well-connected, skyscraper dorms, while artists have begun to occupy and see inspiration in the detritus of the late 20th century skyway network. Cities began to encourage accessory housing, and conversion of garages to apartments.

In the early 2020s, the two-decade long decline in Gas Tax revenue due both to declining demand and increasing electrification of the fleet finally enabled the push for mileage fees. The Green-Libertarian Coalition Government taking office in 2025 enacted a number of reforms to get the federal government out of local transportation, and encourage states to toll their highways. While gas taxes were eliminated, refinery taxes were implemented. The government also put in place carbon and other externality taxes to replace income taxes. More importantly, agencies implemented off-peak discounts, with higher peak prices. Trips that were not urgent at rush hour on Tuesday, Wednesday, and especially the very busy Thursday afternoon in the summertime turned out not to be particularly urgent at all, and total travel dropped more.

By 2025, some cities began to outright ban cars within core areas. Since most residents did not own cars, this became an easy political sell. In those cities, walking, bike, scooter, and bus use soared. This affected not only residents, but anyone going to the city. Cars remain popular for trips outside of cities, but there are fewer cars, fewer car trips per resident, and fewer non-city residents.

Most areas built before 1950 in the US (now housing roughly one-third of the US population) saw significantly improved transit service, with real-time information about arrivals and schedules. With more urban residents and fewer cars, the demand for transit picked up. Agencies were able to put on more buses with the uptick in demand, further encouraging bus use and people abandoning their cars, and now bus-powered urban transit agencies (some of which have a few legacy rail lines) are one of the few profitable branches of government. New autonomous buses have reduced labor costs significantly, and electric power has dropped fuel costs. Transit organizations are now seeing ridership levels they last saw in the 1950s.

Decentralized manufacturing, including 3-D printing on-demand, has begun to diminish long-distance shipping of many goods, which can now be made locally.

Where will the car go? Some warn that the new generation of inexpensive, electrically powered robo-cars will make travel more attractive, and reverse the three decade slide in driving. Others foresee that new light-weight robo-copters will make roads obsolete, and people will just take off from their roofs, and go anywhere they want. Many also suggest that living in cities will lose its desirability with newly low cost housing available in rural areas. But no one thinks congestion is coming back, time is too short to waste it sitting in traffic.


  1. Kaiser Family Foundation says 39% of US workers are “white collar”. While this doesn’t track perfectly with office workers (since some blue collar workers are clerical and can telework, and some professionals (e.g. doctors) are paid for their face time), we will go with that for now. That means we lost 23% of work trips.

    White collar workers are those who self-identify as professionals or managers. Blue collar workers are those who self-identify as assistants and clerical workers, technicians and repair workers, artists and entertainers, service workers, laborers, salespersons, operators, skilled trade workers, assemblers, or former military.

  2. Just like Saturday used to be a regular workday for most people, now many work 4/5 plans. There are many combinations, almost all of which reduce the amount of peak hour travel.
  3. Hipsters began to leave the city, and moved to the now ironic suburbs among the working class immigrants.

12 thoughts on “What happened to traffic?”

  1. Randall O’Toole should comment on this.

    I think this is a fascinating theory. I actually hold with Future 2, but I’d be happy if we did end up with Future 3. The trend should be clear in a few years.

  2. Mass transit systems will die as Google cars evolve into a personal transit vehicle requested by voice command ( sam, come to the front door) where your car, or an instant rental,picks you up and takes you where your want to go. The cars automatically communicate with each other and set up car-trains following each other at 2 cm (super drafting), obtaining better passenger mile efficiency than rapid transit systems with their variable load factors, while taking people from point X to point Y rather than station A to station B. After dropping you at point Y, the car goes and parks itself or is rented to someone else.

    This elimination of human reflexes and inability to know what the cars around you are planning to do, doubles to triples the lane capacity of every highway in the world. The passengers/hour/lane on a highway becomes higher than mass transit with steel on steel wheels and fixed rail. The rail will still need large distances between trains that can’t stop fast, even with automation.

    California will have a massive half finished bullet train white elephant and go broke. This revolution to driver-less cars is only 20 years away, unless the special interest, lawyers and politicians kill the concept in this country and we end up buying Chinese technology in 30 years.

    1. It could be even shorter than 20 years. I think Google’s test car has done a half-million miles without incident. So technologically it’s there. The economic push behind it will be powerful, because there will be a lot of money to be made deploying them as taxis. So it’s really just a question of how long it takes for the regulators to get out of the way.

      1. I was looking at 20 years as 10 doubling times on the electronic cost curve (factor of 1000 on performance/cost curve). That would drop the cost from the 100+K numbers to a reasonable cost with 10 times the performance of todays Google cars. Some will be available early on higher end cars as rich older people loose their drivers licenses and still want/need their car with an automated chauffeur. Full time drivers are only for the super rich.

    2. “better passenger mile efficiency than rapid transit systems with their variable load factors” – I don’t follow. Are you saying that single-occupancy vehicles stacked in a row can be more efficient than a bus with average ridership? A bus weighs about ten times as much as a car, so as long as your bus can average more than ten people, it should use less energy per person.

      You’re probably right about transit systems in suburban areas, but within cities, the limiting cost for transportation isn’t fuel but space. Even if you imagine perfect drafting, you can’t fit more than about three cars in the space that one bus takes up, so as long as a bus averages at least 5 people it can create enormous savings in road space (and thus congestion). And in cities, the fact that the buses only stop at stations isn’t really much of a limitation. Especially once you consider that self-driving technology will apply to buses as well, so agencies can afford to keep running them every 5 minutes all night long (when they’ll still be averaging more than ten people per bus).

      1. With modern tires on concrete, rolling friction is small and the large term is aerodynamic losses. The other big in trafic loss, that is weight per passenger related, is breaking, but with hybrid or electrical drive trains, this is eliminated (my Prius with a 140,000 miles is on the original brakes). A mild evolution to a rounder front end and something like the back end of a Honda Fit would make a very aerodynamic surface at 2 cm between vehicles.

        Automated bus lines with high flexibility would be competitive in some applications ranging from sports events and commuting with large traffic to or from a point source at specific times. Even in cities, doubling of lane capacity is possible and that would eliminate most congestion in most not all cities. Imagine the signal changing and the whole line of traffic moving as a unit with only gaps in the right places to not block cross traffic when the lane stops again.

        However, I expect private automated vehicles, including taxi service, long before the transit unions will allow elimination of bus drivers.

    3. A conventional transit bus holds up to about 90 passengers (seated + standing). An articulated bus holds up to 130+. During rush hours in urban environments these are frequently fully packed. Replacing just one of these with self-driving cars would put about 90 to 130 more vehicles on the road. Even with zero gaps between the vehicles, replacing all busses in use in a city with self-driving cars would mean unending gridlock, especially in the city center.

      Light rail vehicles hold up to about 220 passengers per typical double car set. Commuter and rapid transit rail hold about 150 passengers per carriage, with typically 6 to 10 carriages per train, for a total capacity of up to 900 to 1500. Individual vehicles are never going to be able to compete with this on a capacity per road surface area basis.

      Right now rush hours already entail gridlock in urban areas. Replacing the high capacity vehicles (busses/trains/etc.) already in use there with self-driving individual vehicles, regardless of their coordination, is simply not workable.

      As for super drafting, this has been found to not be feasible at highway speeds due to a variety of factors such as road conditions, debris, and interactions with any non-self-driving vehicles on the road. Below highway speeds there is not enough benefit to super drafting to make it worthwhile. Brand new, perfectly clean, perfectly maintained highways would need to be built, dedicated only to self-driving vehicles. This is unlikely.

      Of course off of highways self-driving vehicles would lose the potential improved passenger mile efficiency from super drafting anyway.

      The per-mile prices for hired self-driving car trips are going to start at the level of taxi trips, if not higher. This will be a huge stumbling block in adoption vs existing transit. Transit isn’t suddenly going to jump in price, and hired self-driving cars aren’t going to drastically drop in price to be competitive. In the meantime there will be many forces at work acting against the adoption of hired self-driving cars, such as taxi drivers and transit unions. The owners of taxi companies may even act against the adoption of self-driving cars in order to preserve their old business model. (Startups with fleets of self-driving cars will be able to compete with established taxi companies who have high existing overhead and legacy costs, such as employee pensions. A taxi company who tries to directly compete with these by adopting self-driving cars themselves will already be at a disadvantage, so they’ll more likely try to force the startups to incur regulatory hurdles and costs which they themselves have already satisfied.)

      High-speed or commuter rail and self-driving cars are actually great complements to each other. Self-driving cars provide the last mile service, picking up or delivering people directly to and from homes, businesses, and other destinations. Self-driving cars are more reliable than human-driven taxis, they have more capacity since there’s one more seat without the driver, and they’re more adaptable as you can call for a vehicle that better suits your passenger and/or cargo capacity needs. Rail provides faster, higher capacity transportation between urban areas (150 to 200+ MPH / 250 to 320+ km/h for high-speed rail), and it provides better on-board amenities for trips of several hours, such as being able to stand up and walk around, use the on-board restrooms, visit the dining car or snack bar, etc. Having reliable self-driving cars at your destination means having less incentive to drive your own personal vehicle to a distant location to ensure you have point-to-point transportation there. This will save wear on owned vehicles.

      Even without using local transit, many people who live in urban areas and find that shared or hired self-driving cars are sufficient for their needs are not even going to own their own vehicle. Hiring a self-driving car for a long trip is then likely to be much more expensive than taking high-speed rail and then using self-driving cars only at your destination for the last mile–not to mention slower.

      The antagonistic attitude of self-driving car proponents against busses and trains baffles me. There’s no way that self-driving cars are going to replace all mass transit, yet their proponents keep sharpening their blades and licking their lips, seeing mass transit as some beast that needs to be slain.

      As far as “California will…go broke” due to high-speed rail and self-driving cars taking over everything: In case you hadn’t noticed it so happens that Google themselves are based in California. Along with Tesla, and Apple, and Intel, and on and on. Plus California’s economy would rank 8th in the world if it were an independent country. So, as far as what I consider misguided arguments between high-speed rail and self-driving cars, California looks like it’s going make out alright either way.

  3. Buses do have their place, as I mentioned, but can’t handle the last mile problem. The only thing I have against buses is public bus companies that have exemptions to axle wt. rules designed to prevent damage to our roads. Note that private bus companies have two axles in the back (an extra cost), to comply with the law. Highway damage is very non-linear with weight and increases dramatically at higher weight.

    The bullet train in California will never work like the propaganda sold to the voters claimed. The budget is already out of control, it won’t be high speed for the last 50 miles into any of the cities, the politically connected contractor has a history of cost overruns in LA and automated cars will provide almost the same door to door time from LA area to the Bay area. All it will take is one religious nut bombing a train and we will have TSA security theater at the rail stations adding hours to the trip time. On long haul, planes will beat trains, especially if TSA expands their control to trains.

    It will take 20 years or more to build the Bullet train in Ca. and by then Google cars will be common and dominate highway 5 competing with the Bullet train. The bonds financing the boondoggle will take another 30 years to pay off. In 50 years, the automated cars will be more than smart enough to easily handle all your objections and perfect road requirements — if the first car sees a pothole, so do all the rest and with dynamic springs and damping float over the defect.

    Fixed rail is just that, fixed. It can’t adapt to the future and will go the way of the canal/barge systems of a few hundred years ago. Passenger rail has been a money loosing system for half a century and only kept alive by politics, especially against buses. Steel on Steel can’t handle the noise issues along the lines. I you lived near Caltrain going up the SF peninsula through Silicon Valley and had been woken up, you would know why, even in super rich Palo Alto, housing next to the line is $300,000 cheaper for the same house a mile away.

    1. You’re conflating a bit, there. You bring up highway damage from public transit busses, but few public transit busses ever spend much time on highways. People taking inter-city public transit that would be done via busses on highways are more likely to travel via rail.

      Your statement “All it will take is one religious nut bombing a train” is pure FUD. Trains are common worldwide (high speed and otherwise) and this is not a major risk, even on the Eurostar through the Channel Tunnel, which would be a much more high profile target. BTW, there are full security checks for travelers on the Eurostar, however the recommended check-in time is only 30 minutes in advance, and only 10 minutes for business class.

      For many people the stations for CAHSR will also be closer and more convenient to get to than going to the SF or San Jose airports in the Bay Area, or Burbank or LAX in the Los Angeles area. This can save a significant amount of time over going to and from the airports which by necessity are far from the city centers.

      The corridor between San Francisco and Los Angeles is already fairly crowded with both airline and automobile travelers, especially around the holidays. The airports are at capacity for that corridor, and they have no room left to add runways to increase this capacity. As the state continues to grow, forcing all the additional travelers onto I-5 and/or 101 in self-driving cars will make that driving experience even more miserable. Does anyone really enjoy being stuck in traffic in or out of the Bay Area or the LA area along that corridor, regardless of whether or not you’re the driver? No, of course not.

      A 2 hour 38 minute high speed train ride between SF and LA will be heaven compared to the current drive time of around 7 hours, plus an additional 1-2 hours stuck in traffic if your timing is bad and you hit rush hours (which seems to be practically 24 hours in LA), or it’s around the holidays.

      Cost-wise, CAHSR is currently projected at $68.4 billion. In comparison the projected cost for equivalent capacity increases over the same corridor for highway and airport construction (assuming the room for that expansion was even available) is $158 billion.

      Self-driving cars are an unrealistic “solution” for dealing with increasing capacity demands within this corridor. Why some self-driving car advocates promote them as such boggles me. (I consider myself a self-driving car advocate. I’m just a more realistic one, with an understanding that they are not a magic wand that will solve all transit problems and replace all other ground-based modes of transportation. I favor mixed-mode travel, with air or rail for longer distances, and then self-driving cars for point-to-point last mile service.)

      As for revenue, higher speed passenger rail services are actually frequently profitable. For example, revenues on the Acela Express on the east coast generate a surplus. The Eurostar was initially underperforming, but it’s been profitable for a while now. Additionally its fares have dropped significantly, its passenger numbers keep going up, and it’s taken over more than 70% of the passenger business in its corridor. The airlines fought against it at first, but at this point they probably don’t mind so much because it allows them to shift their capacity to longer, more profitable routes. It wouldn’t be surprising to see the same thing happening due to CAHSR in the corridor between SF and LA.

      Regarding living “near Caltrain going up the SF peninsula,” funnily enough I am an SF Bay Area native and my bike ride to school in Palo Alto took me across the Caltrain tracks twice every day on weekdays. Your characterization of the issues in that corridor is exaggerated. There are indeed some noise concerns, and I personally hate how loud the current Caltrain diesel sets are. They’re planned to be electrified, however, and that will make them much quieter as well as less polluting, plus it will allow frequency increases and direct service into the Transbay Terminal in downtown San Francisco.

  4. “Since most residents did not own cars, this became an easy political sell. In those cities, walking, bike, scooter, and bus use soared. This affected not only residents, but anyone going to the city. Cars remain popular for trips outside of cities, but there are fewer cars, fewer car trips per resident, and fewer non-city residents.”

    Sounds like Europe to me…?

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