With fall colors reaching their peak, Colorado transportation officials are warning that traffic congestion could also peak this weekend.

The Colorado Department of Transportation in a news release Thursday said drivers should expect another busy weekend of travel along the Interstate 70 mountain corridor, with heavy leaf-peeping traffic likely both eastbound and westbound.

Drivers should also expect “extreme congestion” along U.S. Highway 285, especially between Fairplay and Denver, due to people heading to Kenosha Pass — a popular spot for viewing the fall foliage.

Based on data from this weekend last year, traffic volumes were among the highest of the fall season, according to CDOT. Due to the congestion, the transportation department said it had to meter traffic at the Eisenhower-Johnson Memorial Tunnels for 11.5 hours, from 11 a.m. to 10:30 p.m. this weekend last year.

Westbound travelers last year also saw significant delays from about 9 a.m. to 5 p.m. between Evergreen and Georgetown, an unusual pattern for this time of year, according to CDOT. The delays were reportedly driven largely by the number of day-trippers who wanted to see the leaves changing in the High Country.

Last weekend, traffic on I-70 peaked at 6 p.m. on Friday, although speeds at Floyd Hill were below 10 mph from noon to 7 p.m. due to the congestion, the news release states. Peak traffic Saturday occurred between 10 a.m. and 3 p.m. and Sunday traffic peaked around 11 a.m., according to CDOT.

Drivers this weekend should expect heavy traffic heading westbound late morning through early afternoon and then eastbound from late morning well into the evening. To avoid the worst congestion, it is recommended to leave early or late in the day. Travelers should also be cautious when seeking alternate roads because local roads such as Guanella Pass cannot accommodate interstate-level traffic, according to transportation officials.

Local authorities are also reminding drivers to park only in designated areas, including on county roads and mountain passes, so as to not block emergency vehicles.