It is possibly one of those statistical blips. Just because the tread is, for example, down, doesn't mean every figure would be down. The thing is that if there had been a 50% reduction in KSI's in Telford, the camera partnerships would be jumping up and down about how great they were, it would be all over the news, the sun would always shine and the birds would always sing, etc. But has the blip has been the "wrong" way, they will try to keep quite, they may well have some gentle mutterings about the medicine not working so the dose needs increasing.
The increase is only 20 KSI's, so a couple of bad crashes out of the norm could have caused it. Next year the KSI's will go back to tread and the camera partnerships will be rejoicing about the 50% reduction, while we sit here and have wry smile