TECHNICAL MEMORANDUM GRADE SEPARATION FEASIBILITY STUDY
INTRODUCTION The Village of Downers Grove’s Comprehensive Plan identifies a goal of providing a “balanced transportation system that ensures the safe and efficient movement of vehicles, pedestrians and cyclists.” The Plan acknowledges that the presence of the Burlington Northern Sante Fe Railroad (BNSF) crossing east to west in the center of the Village impedes traffic flowing north and south in the Village. This is particularly true in the central business district, where not only north‐south through traffic is impeded and delayed, but also local traffic attempting to circulate through the downtown. To the west of the downtown, the BNSF tracks divide residential neighborhoods and separates Gilbert Park and the Maple Grove County Forest Preserve from the large, mature residential neighborhoods to the north creating an impediment to pedestrians and bicyclists attempting to access areas north and south of the BNSF tracks.
To accomplish the goal of providing a balanced, safe, efficient transportation system and to address the specific need to improve north‐south traffic flow for all modes in the downtown, the Village has undertaken a Grade Separation Feasibility Study to identify potentially feasible roadway, pedestrian and bicycle grade separations between Belmont Road and Fairview Avenue (see study area map Exhibit 1).
This memorandum outlines the preliminary findings of the Grade Separation Feasibility Study conducted for the Village of Downers Grove. Five roadway/railroad grade separation concepts and three pedestrian/bicycle grade separations are presented. The five roadway grade separations vary in their location, impacts and traffic patterns. The three pedestrian/bike path grade separation alternatives are located in the same general area (between Lee Av. and Wallbank Av.)
STUDY METHODOLOGY Grade separation projects in a mature community represent a substantial commitment of funds, will have impacts on adjacent properties and will create new and permanent infrastructure that will be a part of the community for the next 40 years and beyond. Projects of this scale need to meet both the safety and mobility requirements of the community, while being a prudent investment of funds, providing value and benefit.
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Downers Grove Grade Separation Feasibility Study Study Area Map Exhibit 1
Early planning decisions have a significant effect on future project costs, impacts to surrounding properties and level of disruption during construction. Expending the necessary time and resources to develop and evaluate a range of solutions early in the planning process will focus future design and funding efforts while providing an optimized solution that meets the multi‐ modal transportation needs and provides the best value.
PURPOSE AND NEED The Comprehensive Plan identifies the constraints and delays to north‐south traffic flow associated with the BNSF railroad at grade crossings. The BNSF railroad also bisects the central business district/ downtown of the Village. A vibrant and successful downtown requires ease of access and parking to attract and retain patrons. A downtown district that is perceived as being “tough to get to” or “hard to move around in” may have difficulty attracting and retaining businesses. In addition to the downtown businesses, there are two Metra Stations (Main St. and Fairview Av.) that result in additional traffic and parking loads in the study area.
Train Traffic The BNSF accommodates both freight and commuter (Metra) train traffic. Metra operates approximately 94 trains on a typical weekday within the study area. Of these, 20 occur during the morning peak period (7:00 – 9:00 am) and 16 occur during the 4:00 – 6:00 pm peak. This translates to a train crossing on average every 6 – 7.5 minutes during these peak periods. The Illinois Commerce Commission (ICC) Grade Crossing Inventory lists an average daily train volume of approximately 160 trains per day in the study area, indicating approximately 66 freight trains per day in addition to the Metra trains. Taking into account that each train crossing represents several minutes (gates down to gates up after train crosses), the volume and frequency of trains results in significant delays throughout the day to pedestrians, bicyclists and motorists.
Vehicular Traffic Traffic data within the study area was compiled from IDOT and Village sources. The table below depicts the Average Daily Traffic (ADT, 24‐hour two‐way total) for the existing grade crossings, as well as morning (AM) and evening (PM) peak hour 2‐way volumes.
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Crossing Location ADT Volume AM (PM) Peak Hour Volume Forest Av. 5,100 490 (250) Main St. 14,100 1,124 (1,260) Washington St. 5,300 520 (610) Maple Av. 8,200 800 (860) Fairview Av. 14,000 1,240 (1,230)
Grade Crossing Crashes A review of crash summaries provided by the Village for the years 2011 – 2013 identified that most of the crashes in the study area involved pedestrians and cyclists. Only one crash appears to be related to a grade crossing and this crash occurred on Main Street. Of the 10 reported crashes, two involved bicycles and eight involved pedestrians. Eight of the 10 crashes were injury crashes.
Project Stakeholders Stakeholders are defined as the ones who determine if a project is a success or failure. There are three kinds of stakeholders:
Financially responsible for funding the project Share in the funding Owners Represent the owner’s interest Manage the project Users Actively use or maintain the project Financially affected by the project Others Environmentally concerned about the project Disturbed by any required change in habits or recreation
Based on a review of the study area and likely partners (funding) in any grade separation project, the following stakeholders have been identified:
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Grade Separation Feasibility Study Stakeholders BNSF Railroad Gilbert Park users Chamber 630 IDOT Bureau of Local Roads Cyclists Illinois Commerce Commission Disabled Community Metra Downers Grove Bicycle Club Pace Downers Grove Economic Development Pedestrians Corporation Downers Grove elected officials Residents Downers Grove Fire Department State Representatives Downers Grove Management Corporation State Senator Downers Grove Park District Traffic (local) ‐ Pedestrians Downers Grove Police Department Traffic (local) ‐ Trucks Downers Grove Sanitary District Traffic (local) ‐ Vehicles Downers Grove Youth Baseball Traffic (local)‐ Cyclists Downtown businesses Traffic (Regional) Downtown property owners US Representative DuPage County US Senators DuPage Water Commission Utilities (public and private) Forest Preserve District of DuPage County
Primary Function of Project Based on the identified stakeholders for this study, a new grade separation project needs to balance mobility against maintaining a vibrant and active community (minimizing impacts). The study area is fully developed. Therefore, the need for a potential grade separation must be balanced against impacts to adjacent properties. The five vehicular grade separation concepts have slightly different primary functions based on the location and connectivity to the existing street network. All five will reduce delays and thereby improve traffic, but there is a subtle differentiator of what type of traffic (local, downtown, through) is the likely primarily benefactor of a grade separation. The five grade separation concepts fall into three basic function categories as identified in the table below:
Basic Function Grade Separation Forest Av. Improve downtown traffic circulation Washington St. Main St. Improve north‐south travel Fairview Av. Improve east‐west travel Maple Av.
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GRADE SEPARATION CONCEPTS Overpass vs. Underpass Grade separation requirements (ICC, BNSF, IDOT) for going over the railroad (overpass) dictate a minimum vertical clearance of 23 ft.‐ 4 inches from the top of the rail to the bottom of any overpass. This typically results in the roadway/bike path elevation being approximately 30 feet above the rail when the structure depth is considered. This would result in roadway elevations comparable to a three‐story building. Taking into account required roadway approach grades and ADA (Americans with Disabilities Act) requirements the approaches for a roadway overpass would have to begin and end over 600 feet (approximately one long city block) on either side of the crossing. For example, if Main St. was to be elevated over the tracks, the approach would start at Curtiss Street on the south and extend approximately 250 feet past Rogers St. Between these locations, Main Street properties would be underneath the structure. The impacts would be significant. Therefore, roadway overpass options are not being considered at any locations.
Pedestrian/bicycle paths can incorporate “switchbacks” to obtain the required vertical clearance in a relatively short area. A pedestrian/bicycle path overpass is one of the alternatives for this study.
Railroad Raise/Lower Another alternative would be raising (or lowering) of the railroad tracks as opposed to raising/lowering of the roadways. However, trains require a much longer distance than vehicles for the same vertical raise. A typically urban roadway with pedestrian sidewalks has a typical grade of five to seven percent (5% ‐ 7%). Trains, such as those on the BNSF line have a maximum grade of half of one percent (0.5%). Therefore, to raise the railroad over the roadways in Downers Grove to an elevation of approximately 20 feet, the track raise would have to start approximately 4,000 feet (0.75 miles) east of Fairview Av. and approximately 4,000 feet west of Forest Av. Elevating the downtown area would therefore involve approximately 2.5 miles of multiple tracks, switches and signals being raised.
Train traffic must be maintained during a grade separation. Temporary tracks, switches are signals are required during construction. For a roadway grade separation, the length of temporary tracks (often called a runaround or shoofly) is relatively short when compared to a 2.5‐mile length of multiple temporary tracks, switches and signals that would have to be adjusted during construction of a full track raise or lowering. Temporary Metra platforms would have to be constructed and adjusted throughout the project to keep Metra open and accommodating passengers.
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The costs to raise or lower the tracks through downtown Downers Grove would be in the order of the hundreds of millions of dollars and could be as much as $500 million. The temporary facilities required to maintain train traffic during construction along with the structural costs of the walls and bridges result in these high costs. The railroads (Metra, BNSF) would likely vehemently object to a track raise or lowering and not participate financially in the project.
ROADWAY ALTERNATIVES A total of five roadway (with pedestrian/bicycle accommodations) and three pedestrian/bicycle‐only alternative concepts were developed. Generalized concept footprints of the alternatives are depicted on the Roadway Underpass Alternatives (Exhibit 2) and Pedestrian/ Bicycle Path Alternatives (Exhibit 3). The alternatives considered are:
Forest Av. (with new Rogers St. extension) Main St. (not recommended for further study) Washington Street: Roadway Underpass Alternatives 7% roadway Sub‐Alternative with Warren Bridge
5% roadway Sub‐Alternative with Warren Bridge Maple Av. Fairview Av. Lee St. underpass Pedestrian/ Bicycle Path Alternatives Wallbank Av. underpass (see overview exhibit) Wallbank Av. overpass
The profiles for the initial screening of the alternatives are based on the two‐foot contour/ Geographic Information System (GIS) data supplied by the Village of Downers Grove. The next step in the study process will be identifying which roadway and pedestrian/bicycle alternative that the Village wants to advance for further consideration. A field survey correlation of the GIS contours will be conducted to refine the proposed profiles along with other studies.
Underpass Cross‐Section: Construction of a new underpass in a mature developed area will be a “once in a lifetime” occurrence. In other words, widening or adjusting a grade separation in future is highly unlikely and cost prohibitive. Therefore, consideration needs to be given to the opening (span) width for future consideration beyond the typical 20‐year planning horizon, even if that width may not be needed for the foreseeable future. For the alternative analyses, a span width wide enough to accommodate four lanes of traffic, on‐street bike lanes and sidewalks has been used to determine footprint and impacts. The typical sections show an “interim condition” section, which accommodates a three‐lane section, and an “ultimate
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Downers Grove Grade Separation Feasibility Study Roadway Underpass Alternatives Exhibit 2
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Downers Grove Grade Separation Feasibility Study Pedestrian / Bicycle Path Alternatives Exhibit 3
condition” section, which accommodates two lanes in each direction. For each alternative three exhibits have been prepared: Typical Section Overview and Impacts Plan and Profile
A description of each alternative is presented below:
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