Though it’s still not clear what lawmakers will agree to take up during next week’s special session, Connecticut truckers would like to see them roll back a scheduled increase in the diesel fuel tax.

Motor Transport Association of Connecticut President Michael J. Riley penned a letter to legislative leaders Tuesday asking for some reprieve from the 5 cent increase in the state tax on diesel, which is scheduled to take effect in July.

Last year Gov. Dannel P. Malloy proposed increasing the tax by 2 cents but the truckers associations agreed to an additional 1 cent to avoid the necessity to repeal a property tax exemption on commercial trucks. Riley said due to the economic reality, truckers are looking for relief from that agreement.

“There are times when government must realistically admit that there is a point of diminishing returns as taxes increase. We believe we have hit that point,” Riley wrote.

At 46.2 cents per gallon, Riley said Connecticut’s diesel tax is already the highest in the nation. On July 1, it will rise to 51.2 cents per gallon. Riley said he’d like to see the legislature reduce the base tax by 2 cents so the diesel tax only increases by 3 cents.

The truckers associations also asked lawmakers to cap the total diesel tax at 49 cents per gallon. The legislature took a similar step earlier this year when they capped the gasoline gross receipts tax as a percentage of no more than $3 per gallon.

“This would provide businesses in the state a predictable maximum tax on the diesel fuel which is consumed in the state,” he wrote.

It’s unclear whether there’s any political will to pass a proposal that would decrease revenue that gets spent on transportation projects.

Andrew Doba, a spokesman for Malloy, said rolling back the dedicated tax, which predates Malloy’s time in office, could hinder plans to improve the state’s transportation infrastructure.

“The funding goes toward investment in our transportation infrastructure, meaning that any loss in revenue would delay long overdue improvements to our roads, bridges and mass transit systems,” he said in statement.