Below is guide for estimating the Federal-aid cost of some basic maintenance, repairs and construction. Please contact LHTAC with any further questions.

1. What is the average cost to build a mile of City Street?

• Cost per mile for a two-lane, parking and sidewalk – $800,000/Lane Mile
• Cost per mile for a four-lane, turn bay and sidewalk – $1,034,000/Lane Mile
• Just for comparison – Cost per lane mile for Rural roads – $720,000 

2. What is the average cost associated with building a bridge in Idaho?

• Local Bridge cost below includes design and construction:
  • Total cost = Bridge Area in Square Foot (SF) X $500
  • Off-System Bridge cost is about $60/SF less

3. What are yearly maintenance costs associated with bridges in Idaho?

• Yearly maintenance cost data is not readily available, but found the following data:
  • Inspection cost – $0.40/SF
  • Patch and repair concrete surface – Substructure – $200/SF, Deck – $150/SF
  • Epoxy overlay – $4/SF
  • Polyester concrete overlay – $135/SY
  • Concrete water-proofing system – $20/SY
  • Joint replacement work – $30k to $40K