After moving more than 12 cents higher per gallon over the past three years, Connecticut’s diesel tax is set to drop slightly on July 1.

It will decline by 0.4 cent to 54.5 cents per gallon, according to the Connecticut Department of Revenue Services. For the past several years the tax has been adjusted annually, based mainly on the wholesale price of the fuel over the past year.

Despite the upcoming drop, the Connecticut Motor Transport Association says the tax, which is the highest state diesel tax in the nation, is still too costly and twice that of gasoline.

Connecticut lawmakers and Gov. Dannel Malloy ordered a full review of the state’s tax system, following the recent adoption of a new budget. Trucking interests there hope it will include a look at the state’s diesel tax.

Read more about it from The Hour.