Police in Wales were cracking down on illegal diesel usage of road users in a two day operation in conjunction with HM Revenue and Customs officers.
The operation that took place in Bedwas and Ystrad Mynach, along key transport routes, was in place to look for dyed diesel fuel being used by motorists.
The action comes after 84 reported thefts of fuel in the Caerphilly area in the seven months from January to the end of July.
Not only were officers testing for red diesel for use in agricultural vehicles, but for other dye coloured diesel, as some haulage and bus companies dye their fuel so it can be traced if stolen.
The penalty for using rebated red diesel can be an on the spot fine of £500 and if a commercial vehicle is found to be using it then the business can also be faced with checks to claim back unpaid duty.
All the vehicles stopped in the two day operation were found to be using legal fuel.