Long Island traffic crawled on first day of LIRR strike. Just wait till Monday, experts say.

Many of Long Island's roads and major arteries into the city slowed to a crawl on Saturday, the first day of the Long Island Rail Road strike. And while experts say it can't all be pinned on the halted service — ideal weather, crashes and other road issues can all affect traffic — they predicted it was a precursor to tortuous driving Monday, if the strike continues.

"I think gridlocks like we’ve never seen before will happen," said Robert Sinclair Jr., senior manager of public affairs at AAA Northeast. "There really are no good alternatives."

LIRR trains came to a halt early Saturday after the Metropolitan Transportation Authority and labor unions representing about half of the railroad's unionized workforce failed to strike a deal on a new contract. The system moves an average of 270,000 commuters on a weekday and around 130,000 each day of the weekend.

On Saturday, vehicle travel times shot up, according to Google traffic data. As of around 4 p.m., a trip from Ronkonkoma to Penn Station took about two hours, a 45-minute increase compared with typical conditions. From Babylon to Penn Station, the ride, typically 69 minutes, also was taking around two hours.

Weekend service on the LIRR has been increasing recently, likely triggering complications for many would-be riders on Saturday, said Kelly McGuinness, director of the Sam Schwartz Transportation Research Program at Hunter College.

McGuinness said the impact of the LIRR shutdown on traffic to start the workweek would be more acute.

The subways will feel more crowded, expanded bus service will likely be packed and additional vehicles on the Long Island Expressway will lengthen commutes.

"It’s going to swell the LIE," McGuinness said. "Plan for extra time."

MTA contingency plan: buses, work from home

The MTA's contingency plan largely relies on employees able to work from home.

But beginning Monday, it'll also offer limited shuttle bus service during peak hours toward Manhattan from 4:30 a.m. to 9 a.m., and to Long Island from 3 to 7 p.m., between six Long Island locations — Bay Shore, Hicksville, Huntington, Mineola, Ronkonkoma and near Lakeview — to the Jamaica-179th Street or Howard Beach-Kennedy Airport subway stations. There also will be limited reverse peak service on some routes.

The MTA’s shuttle bus contingency plan can accommodate just 13,000 during each commute, officials said, about 10% of normal ridership each way.

Compounding issues for drivers are already-inflated gas prices driven by the Iran war. More people will need to rely on filling their tanks, adding costs for commuters.

"It’s bad timing all around," McGuinness said.

Sinclair, with AAA Northeast, said drivers also should consider the increased mileage on their vehicles. Idling cars shift pressure to car batteries, which could mean they’ll burn out quicker than normal, he said.

"If you’ve got family or friends who live in the five boroughs, maybe you want to bunk with them," Sinclair said.

The New York State Department of Transportation is taking steps to limit disruptions to traffic, including positioning tow trucks at strategic locations on Long Island, deploying workers to remove debris and suspending nonemergency construction, said Stephen Canzoneri, an agency spokesman.