The Irish Times motoring section led with a piece last week about the failure of the the Government and the Road Safety Authority to implement their much-vaunted speed camera project. Under the original plan, 600 speed cameras would have been installed on the country's roads. The installation and maintenance of the camera network was to have been contracted out to the private sector. However, it is believed now that the initial costs envisaged were radically underestimated, and so the prospect is much less tempting for any putative operator.

Needless to say, there has been great wringing of hands by the great and the good as a result. But to me, this is a victory for common sense. As evidence from other jurisdictions has shown, speed cameras are far more limited in their effectiveness at reducing road fatalities than we are led to believe.

"Speeding" can take one of two forms. It can mean (a) driving at a speed that is too fast for the road or the prevailing conditions (fog, ice, etc.), or (b) exceeding an arbitrary speed limit on a stretch of road. In some cases, an instance of speeding might be both of these combined, but usually it is one or the other. Situation (a) above is obviously dangerous, whereas situation (b) may not necessarily be. Yet speeding detection and prosecution is carried out pretty much exclusively on the basis of the latter scenario.

To implement a credible speed control regime on the national roads, the authorities must first sort out the speed limits themselves. They had the opportunity to do this in 2005, when we changed from miles-per-hour to kilometres-per-hour speed limits, but this was botched. Uniform speed limits are applied to non-uniform roads. If you drive from Cahir to Portlaoise on the N8, you will see what I mean. From Cahir to just north of Cashel, you have a dual carriageway, built to motorway standards. From then on, it is mostly a wide single carriageway, with hard shoulders. But once you get past Abbeyleix it is a narrow, twisting road, the sort you might expect to be designated as an "R" road. Yet for the entire length of that journey (stretches through towns, villages and roadworks excepted), the speed limit is a standard 100 km/h. Now, for some of that road, the speed limit is too low, and for other parts of it, it is too high. On the dual carriageway part, it is arguably safe to drive at 120 km/h (the arbitrary speed limit for a motorway in Ireland.) On the narrow, twisty part, driving at 100km/h is arguably too fast. However, you risk prosecution for the former, even though the latter is more dangerous.

Consider also, regional roads and their speed limits. Once again, we have a one-size-fits-all policy. There are a number of "R" roads that are former national routes, and are good wide roads and would be safe for 100 km/h. One that springs to mind is the dual carriageway between Naas and Newbridge, or long stretches of the old N1. Then we have roads that are little better than goat-tracks, some of which cannot accommodate two cars passing one another without one having to pull in. Whereas it is safe to drive on the former in excess of the prescribed 80km/h, it would be an act of unbridled lunacy to attempt the same speed on the latter. (The original version of the image above can be seen at IrishSpeedTraps.com)

Speed limits on all roads are fixed, irrespective of the prevailing driving conditions. 120km/h on a motorway with clear visibility may be safe, but in fog or torrential rain it is not. Last March, there was a multiple vehicle pile-up on the M7 in Kildare in which a young woman lost her life. Eyewitness reports told of drivers tearing along the motorway at speeds well in excess of what was safe, yet most of them would probably have been under the speed limit.

The other question that needs to be asked is how much exactly does excessive speed contribute exclusively to accidents. I would guess that it is a lot less than we are led to believe. Yes it is a factor, but it is often in addition to another factor, like intoxication or inexperience or fatigue. Several fatal accidents involve a single vehicle, late at night, with a young driver. Yes, he may have been going too fast, but he could have been drunk or on drugs, or have fallen asleep at the wheel, or just not have the experience to handle the speed he was doing.

Speed detection is done on the basis of whatever the prescribed limit is for the road in question. Whether the driver is driving safely or not is not considered. So you could happily drive at 120km/h on the Fermoy bypass (a motorway) without fear of prosecution, yet if you drive at that speed on the stretch of the N8 between Watergrasshill and the Dunkettle interchange you risk prosecution, even though the standard of the road is exactly the same as the M8.

The other major problem I have with the speed camera initiative is that it was to be installed and run by a private company. Private companies have two motives - to make a profit, and to have that profit grow each year. I'm not criticising that, as that is what private companies do. But the purpose of speed cameras is to reduce the number of people "speeding". So if fewer people are speeding, that means that revenues should be decreasing each year. To counteract this the company operating the cameras would have to install cameras at "softer" locations (like the aforementioned stretch of the N8 in north Cork, or on the N6 between Kinnegad and Kilbeggan, or on the N11 between the Glen of the Downs and Wicklow, or on the Gorey bypass, etc., etc.) in order to keep revenues up. Instead of prosecuting unsafe driving, they would be persecuting drivers who happened to be exceeding an artificially low limit, but were still driving safely. It would lose credibility very quickly.

The issue of speed and road safety is a lot more complex than is often presented. It requires a fine balance between credible speed limits and effective enforcement. Speed cameras, particularly privatised ones, are a blunt instrument, and we are better off without them.