New York state on Wednesday joined California and Hawaii with an average above $4, Lardear said.
In Southeastern Pennsylvania, according to AAA, Wednesday's average price was up 32 cents from a month ago, to $3.78 a gallon. In South Jersey, where the state gas tax is lower, the average was up 33 cents during the same period, to $3.60.
To help motorists cope with higher costs, there are several smartphone apps.
GasBuddy, by GasBuddy Organization Inc., is free for multiple platforms. The app depends on its thousands of users to report prices at the pump when they fill up. As an incentive to participate, the developer is giving away $250 in gasoline every week.
Your phone's location service allows the app to find nearby gas stations and their prices, including how long it's been since the price was reported. You can choose to view the list starting with the lowest price, or the shortest distance from wherever you are.
Most of the prices I saw for my neighborhood had been reported to GasBuddy just a few hours before. Tap on a station entry to see details for different fuel grades and to get a map or directions.
MapQuest Gas Prices, free from Mapquest Inc. for Android and iPhone, takes the Oil Price Information Service, or OPIS, instead of user reports in giving gas prices. These prices are self-reported by stations, and Mapquest says it doesn't use any figures older than 48 hours.
Extras you get from Mapquest include turn-by-turn voice directions to the station you choose, and filtering that allows you to select hard-to-find E-85 ethanol-laden fuel in addition to standard grades.
Got an electric car? You suddenly look lucky. And, you could use PlugShare, by Xatori Inc., which is free for iPhone and Android, to locate charging stations.
PlugShare finds a nearby station, lets you know whether it's in use, and what it costs to plug in. Some stations are free; some are "off-line" or otherwise unavailable. If you need to, you can send word of a location by text, Twitter, Facebook or e-mail.
AAA's Lardear said gasoline's price spike - up daily for the last 34 days - is being fueled by perceptions of an improving world economy, East Coast refinery slowdowns, and speculators.
When will there be relief at the pump?
"Not really anytime soon," Lardear said. "I think we're going to see prices continue to spike through April," with the national average topping out about $3.95 a gallon.
Contact Reid Kanaley at 215-854-5114, firstname.lastname@example.org or @ReidKan on Twitter.