Three Mile Speed Study

Memorandum

To: Bob Vosen, P.E. – Missoula District Administrator

From: Stan Brelin II, P.E. – Traffic Operations Engineer

Date: July 24, 2024

Subject: Speed Limit Recommendation

Three Mile Drive / Farm to Market Road (U-6706 / S-424) – Kalispell

Please present the following report to the City of Kalispell and Flathead County for review and comment. Inform them that we would prefer to receive all comments in writing within the next 60 days. Comments not received within 120 days will be regarded as concurrence with the findings of this report. Their comments along with the Department’s final recommendation will be presented to the Montana Transportation Commission for action.

Introduction

In July of 2022, the City of Kalispell requested a speed and corridor study be performed on Three Mile Drive from Meridian Road to 800-feet west of the approach for the Meadows Edge subdivision “for necessary safety and service level improvements for capacity, intersection controls, and access controls”. After multiple discussions, MDT and the city came to an agreement to perform a speed study on Three Mile Drive and Farm to Market Road. Safety would investigate crashes along Three Mile Drive focusing on some of the intersections. An actual corridor study was determined to be inappropriate due to work already being completed by MDT and the City of Kalispell as well as existing plans to improve the road. After reviewing the study area and previous speed studies, it was determined this speed study would begin at the intersection of Meridian Road and continue west and north to milepost 6 near the intersection with Old Reserve Drive. This would allow for the review of the varying speed zones throughout the study area, as well as the Kalispell Middle School and West Valley Elementary School Zones, all of which have seen substantial changes since the last study.

 

Site Characteristics

Three Mile Drive and Farm to Market Road became part of the state secondary highway system in the early to mid-1930s as an improved gravel road. The existing alignment appears to have been surfaced as early as 1956. The last improvements were resurfacing projects which occurred in 2004 and 2009. Most of the study area was improved through project STPS 424-1(6)0 from milepost 0 to milepost 5.6. Project SFCS 424-1(5)6 resurfaced the study area from milepost 5.6 to the end of the study area. There was one project, NH 15(108), that reconstructed a portion of Three Mile Drive when Alternative 93 (ALT-93) was built in 2018.

Within this speed study, Three Mile Drive is part of the urban highway network (U-6706) and Farm to Market Road is part of the state secondary highway system (S-424). Both segments are classified as a major collector. Typical sections for the study area consist of two 12-foot travel lanes (one in each direction) and varying shoulder widths. The urban highway segment has 0 to 2-foot shoulders except around Alternative 93 and approximately between Cottage Drive and Heavens Peak Drive where the shoulders are 4-feet. There are primarily no shoulders on the secondary highway segment, however, in some areas up to a 2-foot shoulder exists. There are left-turn lanes for Alternative 93 and Heavens Peak Drive. Right turn lanes exist for Meridian, southbound Alternative 93, and Camp Crook Avenue. An adequate clear zone is provided for most of the study area except for approximately Four Mile Drive to Snow Camp Road. Although a clear zone is provided, it is not always free of all fixed objects. Sight distance is considered adequate on and along the roadway as the alignment is primarily both tangent and flat. There are four curves and some shrubbery that may create some sight obstructions, but all approaches appear to have adequate sight distances for the posted speed limit. No shoulder rumble strips exist within the study area. There are centerline rumble strips for the majority of the study area except from Meridian Road to Wyndover Hill Drive and around the intersection with Old Reserve Drive. Passing is not permitted until west of Blue Crest Drive. There is approximately 1.9-miles of passing zones for both eastbound and westbound traffic, approximately 32-percent of the study area.

Average annual daily traffic volume from 2022 range from almost 2,300 vehicles in the rural secondary segment to over 6,000 vehicles within the urban highway segment. Peak AADT was primarily observed in 2021 at about 6,600 vehicles in a portion of the urban segment and around 2,800 on the secondary segment. There was a segment on the urban highway segment that peaked in 2022 (Northern Lights Boulevard to Mountain Vista Way). The last segment of the study north of Old Reserve Drive also had a peak AADT substantially greater (4,037 vehicles) than the rest of the secondary highway segment. There has been between a 1.5 and 13 percent increase in traffic volumes on the urban highway within the past 5 years. On average there has been about a 16 percent increase in traffic volumes on the secondary highway portion but most of the route has seen around a 25 percent increase over the past 5-years. It should be noted that traffic volumes during the summer months increase by about 16 percent on the urban highway, about 39 percent between Mountain Vista Way and West Valley Drive, and about 22 percent between West Valley Drive and milepost 6.

The roadside environment starts out as urban and then transitions to a more rural setting. Near the intersection with Meridian Road the development can be considered commercial with about a dozen businesses or commercial buildings. Immediately west of this intersection until Alternate 93 the land use becomes suburban residential on small to medium sized lots. West of Alternate 93 the development is still residential suburban, but homes are on small to large lots depending on the subdivision with some vacant land. West of Morning Eagle Drive for the rest of the study the land use is a mix of primarily residential and agricultural development. There is some commercial between Four Mile Drive and Snow Camp Road and institutional development in the form of the West Valley Schools around the intersection with Old Reserve Drive.

 

Speed Zone History

The last recorded speed studies occurred in 2018 and 2003. On Three Mile Drive from Meridian Road to Stillwater Road the speed zones were last reviewed, and changes approved by the Transportation Commission in 2018. From Stillwater Road to US 93 on S-424 or the rest of Three Mile Drive and Farm to Market Road was last reviewed and approved by the Transportation Commission in 2003. The approved speed limits are as follows:

A 35-mph speed limit beginning at the intersection with Meridian Road and continuing west to a point approximately 200-feet west of Garland Street, an approximate distance of 1,800-feet.

A 40-mph speed limit beginning about 200-feet west of Garland Street and continuing west to a point approximately 100-feet west of Empire Loop, an approximate distance of 2,700- feet.

A 50-mph speed limit beginning about 100-feet west of Empire Loop and continuing west to a point approximately 2.6-miles west of Stillwater Road, an approximate distance of 2.7- miles.

A statutory 70-mph speed limit beginning about 2.6-miles west of Stillwater Road and continuing to a point approximately 50-feet east of milepost 5, an approximate distance of 2.4-miles.

A 45-mph speed limit beginning about 50-feet east of milepost 5 and continuing west to a point approximately 700-feet east of Reserve Drive (Old Reserve Drive), an approximate distance of 900-feet.

A 35-mph speed limit beginning about 700-feet east of Reserve Drive (Old Reserve Drive) and continuing west to a point approximately 400-feet west of Reserve Drive (Old Reserve Drive), an approximate distance of 1,100-feet.

A 45-mph speed limit beginning about 400-feet west of Reserve Drive (Old Reserve Drive) and continuing west to a point approximately 1,300-feet west of Reserve Drive (Old Reserve Drive), an approximate distance of 900-feet.

A 70-mph speed limit beginning about 1,300-feet west of Reserve Drive (Old Reserve Drive) and continuing west to a point about 1,700-feet east of the intersection with US 93, an approximate distance of 11.5-miles.

A 45-mph speed limit beginning about 1,700-feet east of the intersection with US 93 and continuing to the intersection with US 93, an approximate distance of 1,700-feet.

A 25-mph school zone active during school hours exists in the 35-mph speed zones for the Kalispell Middle School and West Valley Elementary School. The Kalispell Middle School speed zone is approximately 400-feet on either side of Hawthorn Avenue. A description of the West Valley School Zone was not found. The posted speed limits within this study are as follows:

A 35-mph speed limit beginning at the intersection with Meridian Road and continuing west to a point approximately 200-feet west of Garland Street, an approximate distance of 1,800-feet.

A 40-mph speed limit beginning about 200-feet west of Garland Street and continuing west to a point approximately 100-feet west of Empire Loop, an approximate distance of 2,700- feet.

A 50-mph speed limit beginning about 100-feet west of Empire Loop and continuing west to a point approximately 850-feet west of Four Mile Drive, an approximate distance of 2.3- miles.

A 55-mph speed limit beginning about 850-feet west of Four Mile Drive and continuing to a point 1,570-feet east of Old Reserve Drive, an approximate distance of 2.3-miles

A 45-mph speed limit beginning about 1,570-feet east of milepost 5 and continuing west to a point approximately 790-feet east of Old Reserve Drive, an approximate distance of 780- feet.

A 35-mph speed limit beginning about 790-feet east of Old Reserve Drive and continuing west to a point approximately 570-feet west of Old Reserve Drive, an approximate distance of 1,360-feet.

A 45-mph speed limit beginning about 570-feet west of Old Reserve Drive and continuing west to a point approximately 1,080-feet west of Old Reserve Drive, an approximate distance of 500-feet.

A 55-mph speed limit beginning about 1,080-feet west of Old Reserve Drive and continuing west to a point outside the study area approximately 900-feet east of milepost 16, an approximate distance of 9.9-miles.

A 45-mph speed limit outside the study area beginning about 900-feet east of milepost 16 and continuing to the intersection with US 93, an approximate distance of 1.3-miles.

The Kalispell Middle School Speed Zone is active from 7:00am to 5:00pm and is as follows:

A 25-mph school zone speed limit beginning about 100-feet east of Northwest Lane and continuing to a point approximately 140-feet west of Northern Lights Boulevard, an approximate distance of 780-feet.

The West Valley Elementary School Speed Zone is assumed to be active during school hours but not documented and is as follows:

A 25-mph school zone speed limit beginning about 790-feet east of Old Reserve Drive and continuing west to a point approximately 570-feet west of Old Reserve Drive, an approximate distance of 1,360-feet.

 

Crash and Citation History

Crash history was reviewed for a three-year period from January 1, 2019 to December 31, 2021. A total of 45 crashes were reported along the study segment – 2 suspected serious injury, 2 suspected minor injury, 2 possible injury, 38 no apparent injury, and 1 unknown injury crashes. The average crash rate was 2.5 crashes per mile per year. Many of these crashes occurred at the beginning and end of the study from milepost 0.0 to milepost 1.5 and from milepost 4.0 to milepost 6.0. These two regions had crash rates of around 3.1 and 3.8 crashes per year per mile. The two most common crash types were rear-end (15) and wild animal (13). There was also a noticeable number of right-angle crashes (8). The rear-end and right-angle crashes were concentrated between milepost 0.0 and milepost 2.5 whereas the wild animal crashes were concentrated from milepost 3.5 to milepost 6.0. Of these 45 crashes, only 13 crashes occured under adverse road conditions (ice/frost, snow, slush, wet). Similarly, only 19 occurred under low light conditions (night, dawn, dusk). However, nearly half (21 of 45) of the crashes were related to intersections. Four were driveways or alley ways. The intersections with the most crashes related to them were Mountain Vista and Alternate 93.

Speed played a role in at least four of the recoded crashes. The primary contributing circumstance was wild animal in the roadway (14) followed by failure to yield right of way (8). There were also a significant number of careless driving (7) and following too closely (7) related crashes. All of the following too closely related crashes were rear-end crashes when the lead vehicle was navigating an intersection. Winter road conditions (snow/ice) were present for all of the crashes where driving too fast for conditions was the contributing circumstance. There were also four reckless driving related crashes.

During the same period, the Montana Highway Patrol made 65 traffic stops and issued 90 citations. Thirty-four percent (31 of 90) of the citations involved speeding throughout the study segment. Speeding citations were primarily concentrated from milepost 3 to milepost 4 with 10 citations per mile and from milepost 5 to milepost 6 with 13 citations per mile. On average there were about 7 speeding citations per mile. There were about 3 speeding citations per mile excluding the high-density speeding citation locations. On average speeding citations were written for approximately 12-mph over the posted speed limit. The highest citations, greater than 15-mph over the posted speed limit, were written in the 25-mph, 35-mph, and 55-mph speed zones. In general, however, there were about 12 citations written per mile. About 38-percent of these citations were secondary offences. There were three areas with a concentration of citations: from milepost 0.5 to milepost 1.0, from milepost 2.5 to milepost 4.0, and from milepost 5.0 to milepost 6.0. These areas account for approximately half of the study area but nearly three quarters of the citations.

 

Travel Speed Characteristics

Vehicular travel speeds were sampled directionally at ten locations to develop a speed profile of the 85th percentile speeds and the pace of the traffic stream from which to evaluate the speed limit configuration of Three Mile Drive / Farm to Market Rd. The following spot speed sample statistics begin at the intersection of Meridian Road with a 35-mph speed limit and continues west to the 55-mph speed limit just past the intersection with Old Reserve Drive. Data was collected in May.

Contextual Characteristics

Recently, the National Cooperative Highway Research Program (NCHRP) completed new research for setting appropriate speed limits on rural and urban streets. NCHRP report 17-76: Development of a Posted Speed Limit Setting Procedure and Tool considers contextual aspects of the roadway environment and how it influences operating speed and safety (crashes). The procedure of the tool uses fact-based decision rules that consider both driver speed choice and general safety associated with the roadway. This means the roadway classification, speed, AADT, and other contextual aspects are accounted for when determining an appropriate speed limit.

There are three segments along the study corridor selected for analysis: the urban, suburban and the rural environments.

The urban environment begins at the start of the study area at the intersection of Meridian and ends approximately near Stillwater Road just west of the ALT-93 interchange area. The roadway is primarily two lanes with left-turn lanes at the ALT-93 interchange with two traffic signals at each access. The travel lanes are 12-foot, and the shoulder width varies between 0 to 4 feet, with most of the section having no shoulders. There is a shared use path located on the north side of the roadway that does service pedestrians/cyclists and is separated from the roadway by a buffer zone. Considering the shoulder width does not meet current design standards, there is an elevated access point density and there is elevated pedestrian/cyclist activity along the shared use path, the rounded down 85th percentile should be used when determining an appropriate speed limit.

The suburban environment begins approximately in the area around Stillwater Road and ends near the new development around the area of Morning Eagle Drive. The roadway is primarily two lanes with left-turn lanes located at the intersection with Heavens Peak Drive. The travel lanes are 12-foot, and the shoulder width varies from 0 to 4 feet, with most of the section having 2-foot shoulders. Considering the shoulder width does not meet current design standards the rounded down 85th percentile should be used when determining an appropriate speed limit.

The rural environment begins approximately past Morning Eagle Drive and ends at milepost 6. The roadway has two lanes with no turn lanes present along this section. The travel lanes are 12- foot, and the shoulder width varies from 0 to 2 feet, with most of the section having no shoulders present. There is an elevated all crash rate for this section, however, there is not an elevated injury crash rate. Considering the shoulder width does not meet current design standards and the elevated all crash rate, the closest 50th percentile should be used when determining an appropriate speed limit.

 

e-copies: attachment:

Gabe B. Priebe, P.E. – Traffic & Safety Engineer

Rebecca Anderson, P.E – Kalispell District Traffic Engineer

Brenden Borges, P.E. – Investigations Lead Worker