It's also not THAT MUCH gas. Cars don't use a ton of gasoline while idling. This page (http://greenactioncentre.ca/living-green-living-well/myth-2-...) asserts that cars use 1/10 to 4/10ths of a liter of gas per 10 minutes of idling. Call it an average of .3 liters, which is 0.08 gallons. If you spend 20 minutes a day (a HUGE amount) at red lights, and then your city doubles the length of all red lights, so now you're spending 40 minutes a day (absurd), that means that each day you spend an additional 0.16 gallons.
So at $4 per gallon, that suggests that your cost (not the city's revenue) for this absurd scenario is $0.66 per day. If the city has a completely ridiculous 10% gasoline tax, that suggests that it's getting $0.07 per resident per day. Or $25 per year.
This may not be the most difficult way for a city to raise $25/resident/year of revenue, but it's certainly in contention for it.
$25 per resident per year is significant, $25M a year in a city of 1M. And how is this 'difficult'? It seems like it's a trivial software modification - certainly not $100,000 worth of work.
I agree that it's a bizarre and horrible way to raise revenue, but your calculations actually make it look quite straightforward to implement.
> And how is this 'difficult'? It seems like it's a trivial software
I co-founded a traffic sensing startup circa 2008. At the time, very few cities had centralized control over their lighting systems (LA mostly did for example, most others did not). In fact, most traffic systems we looked into at the time had very little aggregated control at all. You may see situations were a particular busy street had 'linked' control for a series of 5,6 or 7 block in a row, but even that was fairly rare. Most of the time, each intersection has it's own controller, with minimal if any linkage to the outside world. You can usually find the control boxes, they're the randomly placed conspicuous steel boxes somewhat near the intersection. As for a 'software update', in most cases you were talking about an 8bit 8051 MCU switching some relays. A 'software update' involves someone going to each of these boxes physically (thousands in a decent sized city), plugging into some sort of serial port on the controller board, and running a possibly dangerous destructive write on the MCU flash.
Okay, so this whole scenario is absurd, but I'm enjoying the thought experiment. Don't take this post as anything other than fun noodling about -- the fundamental fact is that no city is trying to raise revenue this way.
The simple answer to your objection is that it doesn't matter if you stop at a light for 30 seconds or 60, you still decelerate to a stop and accelerate to your cruising speed again -- the marginal difference is idle time, not decelerate/accelerate time.
"Ah," but you say, "But presumably if the red light is longer, some number of people who would have in the counterfactual world cruised through the green light will instead come to it while it is red, decelerate, stop, and accelerate again."
True enough. But while that light is red, another light is green -- for longer, presumably. So compared to the counterfactual, some cars who would have come down to the stop at the red in the other direction are instead cruising through the intersection.
(I presume, here, that nobody actually just sets the intersection to "all lights red" for extended periods of time. That would indeed increase the gas use of everyone in the city, but it also rather gives the game away.)
Indeed, ignoring the all-lights-red approach, the fact is that presumably however long you set the reds for, the intersection spends 50% of its time red and 50% green (or whatever for more complicated intersections, but the point is, you aren't altering the overall amount of red at the intersection, you're just changing it from many shorter intervals to fewer longer intervals). That being the case, we can reasonably answer whether it's possible to raise revenue at all here. Is every increased stop balanced by a missed stop?
And the answer to that depends on whether it's more or less efficient for overall city traffic to have longer or shorter reds. My intuition fails to provide an answer, and I don't have any formal background in traffic engineering.
But in any case, the difference seems unlikely -- at moderately reasonable red light lengths -- to make drastic changes to the city. At which point the $25/resident/year that I earlier estimated starts to look like a huge overestimate.
TL;DR: There is no conceivable way that cities are cynically lengthening red lights to raise revenue. Not effectively, at least.
