Croydon council responded to FOI request stating it costs £2.5-£3.5k to install traffic islands. The cost of a speed camera installation on the other hand is £85,000 according to Bedford Council, with a £5000 annual upkeep cost.
Croydon cites average cost for roughly such an action at 2,5k - 3,5k in a denial of the FOI request which means there's pretty much no way to know how much it actually costs depending on what they calculate the average on and if you have any idea about the cost of public works that number should strike you as very, very oddly low.
Wiltshire government here cites about 45.000k for a traffic island narrowing a road to one lane, all in all.
The source you cite for the cameras, however, puts those costs for 2 cameras, so 42,500 a pop / 2500 upkeep annual, albeit with returns via fines obviously.
Croydon cites average cost for roughly such an action at 2,5k - 3,5k in a denial of the FOI request which means there's pretty much no way to know how much it actually costs depending on what they calculate the average on and if you have any idea about the cost of public works that number should strike you as very, very oddly low.
Wiltshire government here cites about 45.000k for a traffic island narrowing a road to one lane, all in all.
The source you cite for the cameras, however, puts those costs for 2 cameras, so 42,500 a pop / 2500 upkeep annual, albeit with returns via fines obviously.