san francisco u.s. state gasoline tax rise decades discuss increase condition might ripe propose hike win approval state legislatures tax experts say week low gas price desperate need revenue fix crumble roads post-election period give politicians space tackle controversial issue breathe life efforts raise tax say carl davis research director non-partisan washington d.c.-based institute taxation economic policy 21 state legislatures consider bill aim increase gas tax year davis say state go 10 20 almost 30 years without gas tax rate increase see purchase power tax decimate inflation rat need update say state lot catch do chief among five politically conservative traditionally tax-averse state raise fuel tax rat since 1980s early alaska oklahoma mississippi south carolina tennessee vote u.s. president donald trump november debate gas tax increase state legislatures right fund purchase power deplete last decades state come realize raise revenues maintain transportation assets kevin pula policy specialist national conference state legislatures tell reuters alaska increase fuel tax almost 47 years low rate nation face budget shortfall governor bill walker independent propose triple fuel tax rat session oklahoma low oil gas price create estimate 870 million shortfall 2018 fiscal year republican governor mary fallin speech monday propose increase gasoline diesel excise tax cents 10 cents respectively 24 cents per gallon increase keep oklahoma motor fuel tax rat well national average 29 cents per gallon fallin say mississippi south carolina tennessee gas tax measure state legislatures momentum gasoline tax increase begin 2012. since 19 state raise gas tax include liberal-leaning blue state massachusetts maryland vermont new jersey deep red wyoming raise gas tax 2013 fellow conservative state idaho nebraska 2015. even state pass gas tax increase year could still eventually become law unusual state level see measure propose immediately enact say joung lee associate director american association state highway transportation officials usually take several bite apple say u.s. state see favorable condition gas tax hike