As darkness fell each night over the long Labor Day weekend, the MoPac Boulevard toll lane was conspicuously free of blinking lights, workers and asphalt trucks.

The paving efforts that have dominated the project’s final stages, particularly during the lightly traveled overnight hours, had come to a temporary halt.

Blame Harvey. Officials say the historic storm, both the heavy rain that hit Austin as well as the paralyzing deluges and hurricane winds along the Gulf Coast, probably cost the historically tardy construction project about a week. That and other factors mean that the rest of the northbound toll lane likely won’t be open for business until the end of this month or early October, officials said Wednesday.

And Steve Pustelnyk, the authority’s community relations director, told the agency’s board Wednesday that the southbound toll lane won’t come be ready until early November.

Related: Will drivers use the new toll lanes?

The project was originally projected to be done two years ago, but has been plagued by unexpected underground challenges, labor shortages, a time-consuming move of a city water main not originally in the plan, rainy weather and in-fighting between officials with the mobility authority and its primary contractor, CH2M. And now, a hurricane.

"The stockpiles of materials were drenched from our 7 or 8 inches of rain," Mike Heiligenstein, executive director of the Central Texas Regional Mobility Authority, said in an interview with the American-Statesman this week. "That certainly caused us a problem last week. This weekend was more of a fuel distribution problem. The trucks were having problems getting the (asphalt) product up here."

Some minor work, along the side of the freeway and separated from traffic with barriers, did occur over the weekend, said the authority’s deputy executive director, Jeff Dailey, including installation of sloped concrete surfaces at the edge of the right of way.

Paving began again Tuesday night, Dailey said. And Heiligenstein said the contractors have told the authority that much of the lost ground could be made up during two more major weekend lane closures later this month. However, authority officials had said those two weekend lane closures, and the traffic hassles they create, were a probability even before Harvey hit the state.

Austin drivers for the past couple of months have been dealing first with "milled" pavement on MoPac — the patchy surface left after grinding away existing asphalt in preparation for laying down new pavement — then uneven pavement after that. Pustelnyk said the "level up" paving on northbound MoPac between West Cesar Chavez Street and RM 2222 is almost done, and that application of the final layer should start this weekend or early next week.

Project managers are in a particular hurry because that final surface, a special type of asphalt that throws off less road noise and rain spray, can’t be applied when temperatures remain below 60 degrees overnight.

The toll lanes and reconfigured free lanes, both northbound and southbound, have been complete north of RM 2222 for almost a year, and the authority opened the northbound "express" toll lane in October last year from Far West Boulevard to Parmer Lane, the project’s north end. Officials preferred to wait until the entire 11 miles of the southbound side was complete before opening that toll lane.

The toll lanes will have tolls that vary as often as every five minutes, based on cameras and speed sensors that gauge traffic levels. The point of the "dynamic" tolls is to prevent the toll lanes from becoming overly congested and thus ensure that traffic in them always moves at 45 mph or more. There will be no maximum toll amount.