Overview and Scope

The purpose of the proposed project is to provide a transportation facility that properly addresses existing and projected system deficiencies and seeks to improve the safety and efficiency of the transportation system in northwest Illinois. The US Route 20 improvement would provide a high-type highway with an appropriate connection to the four-lane facility west of Illinois Route 84 (northwest of Galena) and extend 47 miles to the east connecting to a previously approved four-lane facility near Freeport. This improvement and the Mississippi River crossing (Julien Dubuque Bridge) are the only remaining two-lane sections of US Route 20 left to be studied for multi-lane improvements between Waterloo, Iowa and Rockford, Illinois.

The need for the proposed project is based on several aspects of the currently inadequate transportation system. The study addresses the need for the proposed action in terms of regional economic characteristics, system capacity, safety concerns, community access, and system continuity.

Due to the proximity of the Chicago area there has been a dramatic growth in the number of second homes, along with the recent increases in tourism and recreational related activities and shifts in employment trends in the southern and central regions of JoDaviess County, which have all contributed to a doubling of traffic on US Route 20 over the past two decades. Local commuting patterns and increased truck travel have also contributed to the additional traffic on US Route 20. In addition to the significantly increased travel due to the tourist attractions and developments, there are more local trips and greater truck transport demands.

Existing traffic and traffic projections for existing US Route 20 for the year 2020 indicate the need for a four-lane facility. Current IDOT criteria state that a four-lane facility is warranted when traffic reaches a two-way Design Hourly Volume (DHV) of 800. Presently this section of existing US Route 20 generally exceeds this with traffic volumes ranging from 780 to 1100 DHV.

US Route 20 in the project area was constructed through a land corridor whose topographic and geologic features are characterized by undulating terrain, with steep ridges and narrow valleys and bedrock strata that lie close to the surface. These physical conditions directly influenced the highway’s alignment configuration which often followed existing contours of the area's ridges and valleys.

The existing geometry of US Route 20 also reduces the efficiency to move people and goods through the region. Traffic backups develop at many locations behind slow moving vehicles, a result of extensive lengths of no-passing zones, restricted sight distances, steep grades and, generally, only one travel lane operating in each direction. Most of existing US Route 20 between Galena and Freeport does not meet IDOT’s current design standards for rural highways. Nearly 50 percent of existing US Route 20 comprises vertical and horizontal curves that do not meet IDOT’s current standards for rural highways. In addition, more than 10 percent of this section has grades steeper than the maximum grade allowed for a roadway to remain in place.

According to current IDOT design standards for a two-lane roadway, passing sight distance (passing zones) should be available for at least 40 percent of a roadway’s length. Passing zones account for about 35 percent of the roadway. Actual passing opportunities are available much less than this percentage due to the high volume of traffic.

From an operational perspective, US Route 20’s history of relatively high accident rates is indicative of substandard roadway geometry. Although many of the accidents along US Route 20 may be attributable to geometric deficiencies, straightening the curves and widening the shoulders will not correct all the safety problems along this section of US Route 20.

The IDOT Office of Planning and Programming classifies US Route 20 as a Major Arterial Highway within the rural State highway system. In general, this means the route connects large towns or cities, “long-distance trip” traffic generators, and integrates interstate and intercounty services, while providing a high degree of mobility at high operating speeds and direct routing for long trips.

The proposed project is needed to complete the missing four-lane section on US Route 20 between Illinois Route 84 northwest of Galena and the Freeport Bypass. Upon completion of this project and the Mississippi Bridge at Dubuque, US Route 20 would have continuous four-lane capacity through northwestern Illinois and northern Iowa from Rockford to Waterloo.