This bill requires that all Tier I highways in New Hampshire have mileage-based exit numbers. The exit numbering must conform to the U.S. Department of Transportation's exit numbering requirement as outlined in the Manual on Uniform Traffic Control Devices. The exit numbers will be determined based on the mileage contained in the department of transportation linear referencing system. The department of transportation has until the year 2035 to complete the replacement of existing exit numbering. The bill will take effect 60 days after its passage.