Gas prices nationwide have leveled off but they've reached 15-month highs in 14 states.

The nationwide average for a gallon of regular gas is about $3.66. That's above the $3.65 average last month, according to price tracker gasbuddy.com.

Some midwestern states are seeing more dramatic increases in prices because of more demand and the summer switchover to the summer-blend of gasoline at refineries.

In Michigan, gas prices are up 5 percent from last month, averaging $3.96 a gallon. That's up from $3.79 per gallon last month. Illinois' motorists are now paying $3.97 a gallon vs. last month's $3.79 a gallon. Wisconsin is seeing an increase to $3.79 a gallon this month from the $3.59 a gallon of last month.

Alaska hit its 2014 high and is averaging $4.04 a gallon.

Arizona, at only $3.53 a gallon, also hit its 2014 high.

Other states hitting their 2014 highs were: Oregon ($3.92), Washington ($3.93), Missouri and Wyoming ($3.50), Nevada ($3.84), New Mexico ($3.48), North Dakota ($3.60) and Oklahoma ($3.46).

"That's higher than what we envisioned earlier this year, but it factors in the fear premium that is now reflected in crude oil prices,'' Gasbuddy senior energy analyst Tom Kloza says.

Still, Kloza expects prices to level off at $3.75 a gallon and not go any higher than that.

Gas prices were expected to fall after the Memorial Day holiday but they have yet to do so thanks to unrest in Iraq and rising crude oil prices.

Crude oil hit 9-month highs last week after rising tensions in Iraq. Tuesday, crude oil prices are down slightly by 0.61 percent.

Demand for gas is expected to fall over the next decade. Consumers habits are changing and so is technology. Cars are becoming more fuel efficient and hybrid cars are becoming more widely accepted by consumers.

What are the gas prices in your area? Have you changed your driving habits? Leave a comment in the comments section below.