Speed limit laws don't exist to generate revenue. They exist to disincentivize speeding.
If speed limit laws didn't exist, can you imagine lawmakers saying, "We need more money. Hey, I know! Let's charge people money for driving over a certain speed!"
The laws aren't put into place with the "let's generate revenue" mentality, but their enforcement is definitely done with respect to that mentality. If it's all about getting people to slow down, then:
1) Why aren't law enforcement more focused on getting people to slow down than writing tickets?
2) Why do traffic cops have monthly quotas for tickets?
3) In places where monthly quotas are against the law, why do 'performance revues' of traffic cops only focus on '# of tickets' as the largest performance metric? (basically a quota by another name)
4) Why is it so easy to bargain down a speeding ticket in a large city, whereas in a small town they are only willing to haggle on the points on your license (hint: because they still want you money)?
How is a ticket quota any different than a SLOC quota or a SLOC analysis in a performance review?. Quantity of tickets issued is a productivity metric, as flawed as it is. Their existence does not imply that tickets exist for revenue.
Just like no community has ever been found to be shortening yellow light timers after setting up red light cameras, and no cops ever dubiously search cars for drugs so they can seize assets.
Just because they weren't conceived for a purpose doesn't mean that's not how they're used. Speed enforcement is very frequently performed by small town cops sitting on highways that are just barely in their jurisdiction. They're doing it for money, plain and simple.
Where I live, in Chicago, the speed limits are so low on some freeways that 91-98 percent of people are going over the speed limit, and the average speed is over 70mph. So everyone, including the police it seems, agrees that the speed limits here are not for my safety, but exist as a way for the officers to cherry pick essentially any car they want and write them a ticket.
The idea of a speed limit is sound. But there are organizations that work to game the system. A great example is the multitude of sleepy towns right next to highways. They have a police force that is exclusively utilized on the five miles (or less) of highway that officially fall within the town limits, writing tickets to people who pass through. For example, Lindale, Ohio has a population of about 170 people and collects about $800,000 a year from speeding tickets.
My mother got snagged in one of these in Virginia a while back - they have a hill where the speed limit drops from 65 to 45 at the bottom of it, with a specially planted copse of trees where the police sit with their detectors. A quarter mile down the road, they have a specially built parking lot for people to get their tickets. They even provide envelopes and stamps for people to send their checks! Nice people.
Speed limit laws started as a safety thing, then they were a car efficiency thing (during the 70's oil crisis). The problem is that the municipalities started to increasingly depend on the income from traffic enforcement.
No, lawmakers don't say "Hey, I know! Let's charge people money for driving over a certain speed!", they instead say: "lets install these red light cameras on this intersection that doesn't see a lot of accidents.", or "this long straight stretch of highway, with few accidents, but lots of speeding should be better policed". The enforcement of laws becomes more about making money from the tickets than from concerns about safety.
The manufacturers of speed cameras take a percentage, and it is a windfall for the municipality.
I live in an area where stationary speed cameras are around every corner (Montgomery Co, Maryland). I've lived here long enough to know that there's no way the county would spend money on the equipment and man power to maintain and operate that network, just to break even for the sake of safety.
That would only be the case where people accept tolls & toll booths on roads as an acceptable thing.
Sure, they're common in Canada and the US but in some other countries they lead to years of civil disobedience, protests and eventual scrapping by newly elected governments : http://en.wikipedia.org/wiki/Skye_Bridge#Toll_controversy
Speed fines have the semi-respectibility claim of trying to reduce accidents/dangers on the road (with some validity).
