Is leaf peeping or spring break skiing busier on the I-70 mountain corridor? 

Numbers are in from the final weekend of September, and it was officially the fourth-busiest weekend of the year on I-70, according to the CDOT traffic counters at the Eisenhower-Johnson tunnels. 

2024 Busiest weekends on I-70 

  1. 153,343 vehicles in both directions (July 12-14) 
  1. 150,241 vehicles (Aug. 2-4) 
  1. 149,238 vehicles (July 5-7) 
  1. 147,441 vehicles (Sept. 27-29) 

The last weekend in September is historically one of the top-5 busiest weekends on the mountain corridor. In most years, this weekend is busier than the thick of spring break ski season. 

But this only tells half the story. September this year was slower than March, just barely, because traffic took a nosedive after Labor Day. 

  • 143,212 vehicles (Aug. 30 to Sept. 1) 
  • 127,435 vehicles (Sept. 6-8) 
  • 132,615 vehicles (Sept. 13-15) 
  • 137,661 vehicles (Sept. 20-22) 
  • 147,441 vehicles (Sept. 27-29) 

Traffic fell by nearly 16,000 vehicles between Labor Day and the first weekend of September. Since then, it has been growing by 5,000 cars every weekend before doubling down this past weekend, when fall colors were just barely past their peak. Leaf peeping season followed the same trend last year.  

But spring break ski traffic in March. 

  • 134,314 vehicles (March 1-3) 
  • 141,289 vehicles (March 8-10) 
  • 133,324 vehicles (March 15-17) 
  • 138,604 vehicles (March 22-24)