Drivers in the United States were once again putting more miles on their vehicles in September than in the same month in the previous year, according to the Federal Highway Administration.

In its latest "Travel Trends" report, the FHWA says drivers covered 259.9 billion miles in September. This total was an increase of 4.3 percent—10.8 billion miles—over travel in September 2014, reaching the highest total recorded for September of any year in the study.

The seasonally adjusted total for the month was higher, reaching 264 billion miles. This tally is conducted by the Department of Transportation's Bureau of Transportation Statistics to account for factors such as weather and holidays. The seasonally adjusted figure was up 3.4 percent, or 8.7 billion miles, from last year. However, it was also a 0.2 percent decrease from August, a decline of 600 million miles.

Travel has increased when compared to the previous year for 19 months in a row. September's year-over-year increase was also the largest one recorded since January.

Americans drove an estimated 2.36 trillion miles in the first nine months of the year. The moving 12-month travel total reached 3.12 trillion miles in September.

The Northeast region—which includes the New England states, New Jersey, New York, and Pennsylvania—continued to have the smallest increase in travel. The number of miles driven in these states increased 2.9 percent from last year to 38.67 billion miles.

Connecticut had the most modest travel increase in the region, going up 1 percent from 2.64 billion miles in September 2014 to 2.67 billion miles in the most recent survey. This total included 1.91 billion miles on urban arterial roads, a 0.8 percent increase, as well as a 2.4 percent increase on rural arterial roads to 181 million miles.

In Rhode Island, travel increased 3.2 percent from 940 million miles in September 2014 to 970 million miles in September 2015. Urban arterial traffic jumped 3.1 percent to 716 million miles, while rural arterial traffic went up 4.8 percent to 66 million miles.

The eight states in the South Gulf region, stretching from Kentucky to Texas, had the most significant increase in travel. Drivers in this state covered 52.01 billion miles, a 5 percent increase from the previous year.

The 12 states in the North Central region had the most travel overall at 60.28 billion miles, a 4 percent increase from last year. However, North Dakota was the only state to have a decrease in travel. Motorists in this state drove 790 million miles, a 3.6 percent decrease from September 2014.

In the 13 states comprising the Western region, travel increased 4.8 percent to 55.8 billion miles. Travel in the South Atlantic region, which has eight states and the District of Columbia, climbed 4.6 percent to 53.14 billion miles.

Michigan had the largest single state increase in travel, which increased 7.6 percent from 7.98 billion miles in September 2014 to 8.59 billion miles. Other states with major increases in travel included Arkansas, where the distance covered rose 7.2 percent to 2.7 billion miles, and Hawaii, which had a 6.7 percent increase for a total of 1.2 billion miles.

North Dakota was the only state to have a decrease in rural arterial traffic, which fell 1.8 percent, and it also posted a 5.2 percent decline in urban arterial traffic. Alaska and Mississippi also saw reductions in urban arterial traffic, which dropped 0.9 percent and 0.1 percent, respectively.

The FHWA's monthly estimate of distance driven in the nation is issued on a two-month delay. The data in September was collected from 2,332 continuous traffic counting locations, which compare a month's traffic flow to the same month in the previous year. The FHWA says the stations provide a limited sample size, and a more accurate estimate is provided once a year through the Highway Performance Monitoring System.