California motorists are paying the most in gas taxes and getting almost the least in roadway quality.

The average price for regular grade gas in California has again topped $5 a gallon, according to the most recent American Automobile Association report.

Its more than $6 in some areas and the average is up about 20 cents from a year ago, and about $1.50 higher than the national figure.

The difference between gas prices in California and other states: differing policies.

Severin Borenstein, a UC Berkeley economist and the states leading expert on the issue says California's direct and indirect taxes on fuel amount to nearly $1 a gallon.

That's 70 cents higher than the national average in such taxes.

Add another dime for the state's unique fuel blend to battle smog.

That leaves what Borenstein calls the "mystery gasoline surcharge" of about 43 cents a gallon that cannot be directly attributed to oil prices, or California's taxes, or other official factors.

It may be a mystery, but at least some of it can be attributed to the high cost of doing any kind of business in California: rents, electricity, wages, and regulatory overhead, for example.

Even if the surcharge could be eliminated from the equation, California's gas prices would still be at least $1 higher than those in other states.

Despite paying direct and indirect taxes on fuel that are triple the national average, California's motorists are driving on highways that are subpar compared to those in other states.

As of 2020, California had the fourth worst roadway conditions of any state, with just 67% of its more than 26,000 miles of pavement in acceptable condition, according to the Federal Bureau of Transportation Statistics.

For CalMatters, this is Dan Walters.