Image showing aerial view of the new compact roundabout at Spiral Boulevard with three approaches and pedestrian crossings.

HIGHWAY 316, BEFORE & AFTER STUDY

Hastings, MN | April 2024

Overview and Purpose

Image of a stick map showing Hastings, MN and surrounding area with a heavy line on Highway 316 from Highway 61 to County Road 91 to indicate the project area. — Highway 316, Hastings | Project Area

The Minnesota Department of Transportation (MnDOT) wants to understand the impact of the reconstruction of Highway 316 in Hastings, Minnesota. The reconstruction included innovative roadway and intersection design aimed at reducing vehicle speeds and calming traffic.

The reconstruction project started in 2021 and finished in 2022. The roadway changed from a rural highway varying between two and three rural lanes to a divided two-lane urban roadway.

Compact Roundabouts were added at the three intersections of Tuttle Drive, Tiffany Drive, and Spiral Boulevard. Compact Roundabouts have less impact to surrounding properties and more easily fit a roadway corridor's existing footprint.

Tour the Highway 316 corridor with the below animation. This video shows the reconstruction as proposed. The map below provides a tour of the corridor, showing images taken post-construction.

This animation takes you along the Highway 316 corridor showing the proposed reconstruction.

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Hwy 316 and Spiral Blvd Compact Roundabout

Aerial image of highway 316 at 33rd Street West.

Hwy 316 and 33rd St W

Image showing aerial view of the new compact roundabout at Tiffany Drive with four approaches and pedestrian crossings.

Hwy 316 and Tiffany Dr Compact Roundabout

Aerial image of highway 316 at Maher Avenue.

Hwy 316 and Maher Ave

Aerial image of highway 316 at Malcolm Avenue.

Hwy 316 and Malcolm Ave

Image showing aerial view of the new compact roundabout at Tuttle Drive with four approaches and pedestrian crossings.

Hwy 316 and Tuttle Dr Compact Roundabout

Purpose

The purpose of this before and after study is to document the changes in roadway safety and performance in an objective manner, and to determine if the needs of the corridor were addressed with reconstruction.

MnDOT aims to learn the impact of this innovative design as it may have broader application.

Primary Needs, as determined by public input:

Improved access to local businesses and residences
Improved safety for all users
Multimodal options with a trail and improved crossings
Elements to slow vehicle speeds

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Improved Access

This section examines the change in traffic volumes, side-street delay, and midblock activity with the reconstruction of Highway 316.

Traffic Volumes

Turning Movement Counts were collected on Tuesday, September 12, 2023, at eight intersections along Highway 316. Weekend volumes were collected at Spiral Blvd, Tiffany Dr, and Tuttle Dr on Saturday, September 16, 2023.

Turning movements were collected from 6 a.m. to 6 p.m. Peak hours were identified as AM (7-8 a.m.), Midday (12-1 p.m.) and PM (4-5 p.m.).

TRAFFIC VOLUME KEY FINDINGS: Overall, traffic is not diverting from the corridor because of the changes. Heavy trucks are still utilizing the corridor as before for travel and deliveries. Volume on Spiral Boulevard increased considerably due to improved access provided by the roundabout, and the reduction in access at 31st Street.

Graphic showing the volume comparisons of different points along the project area.

Delay

A delay analysis was completed in September 2023 for eight intersections. We identified the time a vehicle joins the rear of a queue to when the vehicle clears the intersection. This was compared to the 2017 delay analysis from the previous Highway 316 Improvement Project Corridor Study Report.

Midblock Activity

A review of midblock activity was performed in three different locations. The review focused on the busiest times along the corridor (6:30 a.m. to 7:00 p.m.) over several weekdays.

Graphic showing the evening peak hour average of side street delays on highway 316 before improvements in 2017 and after improvements in 2023.

Improved Safety

This section examines crash history and roundabout compliance with the reconstruction of Highway 316.

Crash History and Trends

A crash history was completed using all available post-construction data (1/1/2022-12/31/23). Preconstruction crash data was taken from the 2017 Highway 316 Corridor Study.

The bar chart at the left shows crash severity before and after construction, and the table below provides a summary of crash trends before and after construction.

Table listing summary of corridor crash trends before and after improvements.

Bar graph showing crash severity pre and post construction on highway 316. Preconstruction is on the left with a blue bar indicating 74% of crashes were property damage only and 26% of crashes were possible or minor injury crashes. Post construction crashes are shown on the left with a blue bar indicating that 93% of crashes after construction were property damage only, and 7% of crashes were possible or minor injury crashes.

CRASH HISTORY AND TRENDS KEY FINDINGS: Injury crashes have decreased by about 20%. Sideswipe same-side crashes have increased at intersections. Many crash types that result in higher injuries have been eliminated (right angle, left turn, and sideswipe opposing). Rear-end crashes have decreased by 10%.

Roundabout Circulation Compliance

Circulation compliance is whether vehicles traverse a roundabout properly.

During all Peak Periods, the number of vehicles entering these intersections was divided into those circulating correctly around the center island and those driving straight over without adjusting their path. For passenger vehicles, any amount of driving over the center island was considered a violation.

CIRCULATION COMPLIANCE KEY FINDINGS: Compliance ranges from 95% to 99% at the Highway 316 roundabouts. Compliance is lowest in the AM and Midday Peak Periods. Compliance was lowest at Spiral Boulevard in all Peak Periods observed due to a larger amount of vehicles. Non-compliance increases when traffic is slower. Highway 316 roundabouts had similar compliance to comparable locations.

Truck Circulation Compliance

Roundabout compliance was lower for heavy vehicles and trucks towing trailers along most corridors observed, ranging from 84% to 88% throughout the day.

Multimodal Options

This section examines the change in pedestrian activity and pedestrian improvements made with the reconstruction of Highway 316.

Pedestrian Activity & Improvements

This map shows pedestrian activity in the area and the difference in pedestrian activity between 2017 and 2023. Pedestrian activity increased, particularly in the main residential area where sidewalks were missing before construction.

Pedestrian improvements made during reconstruction included:

The addition of a 10-ft wide separated walking/biking trail along Highway 316. This supports pedestrian and bike mobility along the corridor.
The addition of the three Compact Roundabouts. This decreased pedestrian crossing distance by providing refuge islands.
The addition of clearly defined, marked, mid-block crossings at 33rd St W and 37th St SW.
The raised median down the center of Hwy 316 provides a pedestrian refuge when crossing. The median and curbed roadway edges encourage safer speeds.

MULTIMODAL KEY FINDINGS: Pedestrian activity increased. The biggest increase was between Malcolm Avenue and Tiffany Drive where sidewalk/trail was installed.

Elements to Slow Speeds

This section examines the travel times and vehicle speeds along the corridor.

Corridor Travel Time

Pre-construction 2017 data was compared to post-construction 2022 data. Travel time runs were also conducted post-construction in the field in 2023.

Travel time was 2.5 minutes from Michael Drive, south of Tuttle Drive, to Highway 61. This time changed by a maximum of 26 seconds, AM north to south. This change can be attributed to slowing to 15-20 mph to navigate the Compact Roundabouts and the overall slower speeds on the corridor.

TRAVEL TIME KEY FINDINGS: The increase in travel time to traverse the corridor is less than 30 seconds. This increase is attributable to slowing to navigate roundabouts and overall slower speeds on the corridor.

Speed

MnDOT collected speed data pre-construction in 2017, and post-construction in 2022. Additional post-construction speed data was collected over a three-day period in September 2023. The map on the right shows observed speeds before and after the project, as well as existing speed limits.

The box plot below shows that the project reduced the number of high-end speeders. Additionally, more vehicles are traveling at uniform speeds in the residential area of the corridor.

Box graph showing speed range on highway 316 before and after construction.

Summary

Key Findings

Improved Access

Access was improved, shown in the reduction in delay for side street traffic to enter Hwy 316.
Traffic volumes increased since pre-construction demonstrating that the road design did not divert traffic to another route.
Buses and delivery vehicles rerouted to utilize side streets or driveways, resulting in only minimal impact on overall traffic delay.
Garbage and school bus drivers stated it was easier to access Highway 316 after construction from side streets.

Improved Safety

No fatal, serious or minor injury crashes have occurred after the project.
Right angle, left turn, and sideswipe opposing crashes, which are crash types often resulting in higher injuries, have been eliminated.
Circulation compliance is in line with other Compact Roundabout corridors in the metro area.

Multimodal Options

Pedestrian and bicyclist activity increased both along the corridor and crossing Highway 316.
Adding a median refuge and filling gaps in sidewalks increased the safety and comfort of pedestrians.
School bus stops can occur on side streets now with the addition of the trail/sidewalk. Students no longer have to wait for their buses along the highway.

Elements to Slow Speeds

Average time to drive through the area increased by 17 seconds.
The roundabouts provide slowing along the corridor and have created more uniform speeds. Speeds on Highway 316 remain over the posted speed limit, but decreased overall compared to pre-construction conditions.
The number of speeders exceeding 50 mph has been reduced by 12%.