The problem is there's only so much room for automobiles in a city. The more you decrease traffic, the more you'll induce demand to fill those improved traffic flow patterns.
The more infrastructure that is built downtown, the more people want to be downtown.
There's no way to alleviate traffic in large cities with cars; it just isn't possible as long as you require everyone to have a car. Making roads wider just brings more cars as people move farther away and have to drive more, making more traffic and more calls to make more and wider roads, etc.
That sounds like more vehicle miles in downtown areas which are already severely congested. A large part of the problem is that cars are the least spatially-efficient form of transportation: having them drive more miles at peak times isn’t going to work unless we see huge improvements elsewhere, which seems unlikely.
i think the point of "induced demand" is that you sometimes can't really fix -- specifically -- traffic or parking congestion problems by building more. if you widen the roads, in many cases it won't make your commute any quicker. if you add more parking spots downtown, more people will drive downtown.
it's not that there's no benefit to the wider road or parking spots, just that the benefit people really care about -- less traffic and quicker trips, less time searching for a parking spot -- often fails to materialize.
Adding more roads and highways to cities doesn’t seem to reduce gridlock. If anything it releases pent up demand for driving.
One of my favorite demonstrations of how impactful public or alternative transit options can be is this image[1] which shows the amount of space taken up by 69 people in cars, on bikes as well as a bus.
Space for transportation in urban areas is so limited that we can’t continue to grow in the same way without new options outside of using more cars with only 1-2 riders.
The more roadways you build to accommodate cars, the more cars fill up the roadways, as long as more people have cars in the city. [0] On the other hand, public transit can be designed to ease congestion and allow movement between densely populated areas. Moreover, cost of building public transit keeps on increasing [1].
The solution is not more roadways to magically reduce congestion. It's to build public transit today before it gets more expensive. See the success of the Delhi Metro in India, for example, where New Delhi was never built with a local subway system in mind. [2]
That's very true if the goal is to get rid of automotive congestion completely.
The practical solution is to find a trade-off where we allow enough congestion to allow the necessary and important things to move but not too much that allows convenience traffic that makes the city unwalkable and car-dependent.
As we've seen repeatedly in the past decades, increasing potential throughput only leads to increased car use to fill the unused throughput, and you'll rapidly reach the exact same situation as before. Add to that, whatever throughput you add, it will be bottlenecked by the time you reach the next city. Urban areas don't have room for more streets.
The construction of bigger roads is the CAUSE of traffic jams, not the solution. The more you improve a highway system, the more people build and relocate to take advantage of the highway. But you can never upgrade the rest of the city streets to absorb all the cars spilling off the highway. The only solution is to invest in mass transit and vigorously control suburban sprawl (by increasing population density, making downtown living more attractive, and restricting new development anywhere within driving distance).
I don't think that applies. Isn't the point (or one of the main points) of building more roads to make traffic congestion better? The study in this article shows that that doesn't pan out.
It's also true that once a city finally stops ignoring the inadequate bandwidth of an extremely busy road and expands it, new businesses and attractions may want to be built along that more pleasant road leading to more people wanting to take the road.
I agree entirely that a great public transportation system is a much better solution, but for places that don't have one and aren't going to create one, insisting that induced demand makes expanding roads inappropriate is just... wrong.
Ultimately, if falls on cities to provide people with a way to get to where they want to be and leaving bottlenecks in place makes people miserable and stifles the local economy.
There are many multiple reasons that lead to this.
For example, it's usually easier to increase the 'main arteries' of the road network. Just widen the road or build more roads. This option usually goes away close to the destination.
If you just keep building more highways, you end up with hurry up and wait situations where the congestion starts close to the destination and spreads backwards. Cars are waiting to exit highways in the mornings and streets leading to highways are full in the evening.
If you solve all these issues and build enough highways, entries, exists, streets etc. you end with a sparse city. Traffic is faster but distances are long. More traffic is needed because walking distances disappear.
This seems like the same problem with traffic. If fewer people drove we'd have better throughput in our roadways, when the roadways get more efficient more people want to drive, and we have clogged roadways again.
The less you invest in public transportation, the more people will drive. The more people that drive, the slower traffic gets. If you just widen the road, all you do is increase the amount of cars that drive. If people can't get to where they are going via public transportation, then they are going to drive instead, increasing congestion. Would recommend watching this video on it:
The more infrastructure that is built downtown, the more people want to be downtown.
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