NS741: Operational characteristics of conventional and electric-assisted bicycles and their riders
Problem
The MnDOT Bicycle Facility Design Manual and the AASHTO Guide for the Development of Bicycle Facilities are the go-to resources for the design of bicycle facilities, and the values in these manuals are used to make decisions on bicycle projects every day. However, some of the values and calculations presented in these guides are based on information collected 30+ years ago and a lot has changed since then. For one thing, people of all ages and abilities ride bikes, and many design values are based on studies from the 70s and 80s that were conducted only on adult men.
A limited amount of research has been done in the last 20 years that has improved our understanding of bicyclist acceleration and speed on conventional bicycles, but more information is needed related deceleration, braking, lean angle, turning radius, and coefficients of friction. Advancements such as disc brakes, e-assist bicycles, and adaptive bicycles mean that even the limited information that we do have may become out dated.
In particular, e-bikes add another layer to the mix by making larger bicycles like cargo bikes more accessible. With increased accessibility, a wider range of bicycles are becoming prevalent. At the same time, e-bikes are the shiny new thing and there has been a substantial amount of research into very specific characteristics of e-bikes and their users. While information on battery range and user risk taking is useful, we are still missing basic information about both conventional and electric bicycles.
Objective
The objective of this research is to collect information about basic bicyclists operating characteristic of conventional bicycles, electric assist bicycles (e-bikes) and their riders. In particular, this project will evaluate bicycle coefficient of friction, deceleration, braking distance, and turning radii over a wide range of bicycle types and users. Other characteristics of interest include operating speed under different conditions such as on/off-road, uphill/downhill, and with/without electric assist. Researchers should identify the characteristics they believe will be the most impactful and efficient to study based on their understanding of how these values influence bicycle facility design.
While e-bikes and their e-assist features are of interest to this study and cannot be ignored, the objective of the proposed research is not to focus on e-bikes alone. MnDOT’s design guidance addresses a large range of users and vehicles so the research study should be designed to capture a range of data.
Previous research
The body of research that this study will build on is small. The three studies listed in item iii are the most recent studies known to have focused specifically on bicycle/bicyclist characteristics. Although, more recent studies in the attached literature review may include some of this information.
- Monsere, C., Figliozzi, M., Thompson, S. & Paulsen, K. (2013). Operational Guidance for Bicycle- Specific Traffic Signals in the United States. Report No. FHWA-OR-RD-14-06. ODOT Project SPR 747.
- Portland State University observed 4,673 bicyclists at 13 signalized intersections in Portland and 4 other communities in Oregon and measured reaction times, crossing times, waiting time, gap acceptance, and saturation flow rates.
- Assumed acceleration rate in GDBF 5th edition and MnDOT BFDM increased significantly as a result
- Parkin, J. & Rotheram, J. (2010) Design speeds and acceleration characteristics of bicycle traffic for use in planning, design and appraisal. Transport Policy, 17 (5). pp. 335-341. ISSN 0967-070X.
- University of West England, Bristol studied 26 bicyclists (12 men, 14 women) for speed, acceleration, level of effort (watts), and impact of grade
- Assumed impact of grade changed in GBFD 5th edition and MnDOT BFDM
- Landis, B., Petritsch, T., Huang, H., & Do, A. (2004).Characteristics of Emerging Road and Trail Users and Their Safety. Transportation Research Record: Journal of the Transportation Research Board, (1878), 131-139.
- Data collected on 881 users in Florida, Maryland, and California
- Measured length, eye height, width, acceleration, speed, perception/reaction time, braking and friction, deceleration, and lateral operating space
- Assumed co-efficient of friction for braking on dry pavement changed in GBFD 5th edition and MnDOT BFDM
Expected outcomes
- New or improved manual, handbook, guidelines, or training
Expected benefits
The numbers 1 and 2 indicate whether the source of the benefit measurement is from:
- A specific research task in your project that supports measuring this particular benefit, or
- Implementation of the research findings (anticipating positive results)
- Decrease Engineering/Administrative Cost: (2)
- Updating our design guidance to better reflect user and vehicle characteristics will improve efficiency in project development. Increased certainty in design guidance will reduce the need to arbitrate recommended values and reduce project development costs.
- Environmental Aspect: (2)
- Designing and constructing more comfortable bicycle facilities based on real-world data about bicycles and their users may lead to mode shift and VMT reduction.
- Safety: (2)
- Several critical safety calculations such as stopping sight distance are based on these values, and this information should be based on real-world values to achieve the best safety outcome.
- User Benefits: (2)
- Designing and constructing bicycle facilities designed based on real-world data about bicycles and their users will lead to more reliably comfortable trips and a better user experience.
- Other: (2)
- The MnDOT Bicycle Facility Design Manual is one of the most advanced in the nation, and is used by many Minnesota agencies to plan and design for bicyclists. Updating this information will help MnDOT and its partners stay ahead of the curve with emerging technology. In addition to supporting MnDOT's understanding of bicyclist operational characteristics, this research will contribute to the national body of knowledge on the subject.
Technical advisory panel
- Jamal Love, MnDOT Geometrics
- Scott Thompson, District 7 Traffic
- Rueben Collins, City of St Paul (pending)
Supplemental information from the champion
- Is there a list of exhibits in the BFDM that are intended to get update with this guidance and if so, is this prioritized in the event that project funding isn't able to meet all needs?
- I don’t have a particular list in mind, I’m looking to the proposers to identify what characteristics are most important (how the influence design decisions) and also which are most realistic to measure. That said, the characteristics in Exhibit 4-3 are of particular interest because the source information for those is so sparse. We have also had a lot of conversations internally about lateral shy distance (Exhibit 5-3) and horizontal curve radii (Exhibit 5-7).
- The objective states "...this project will evaluate bicycle coefficient of friction, deceleration, braking distance..." Is there a difference between deceleration rate and braking distance that is desired?
- This is a fair question, as there may not be much of a difference. I was thinking about it as deceleration being the rate that a bicyclist naturally feels comfortable slowing for a known stop (e.g. approaching a red light) whereas braking distance is more of an urgent stop (e.g. avoiding a collision). One is more about the user the other is more about the equipment. I suspect that with the introduction of heavier bicycles, the emergency stopping distance has probably increased, but that the more user driven values might remain the same.
- What is the timing of the next major update of the Bicycle Facility Design Manual and how does that line up with this project?
- We are hoping to initiate the next bike manual update in 2025, which will probably be a 2 year process. The update will be driven by the release of the 5th edition of the AASHTO bike guide, but we’ve already incorporated the values from that document. OTAT occasionally does interim bike manual updates, so while we’d ideally have the information in 2026 or early 2027, it’s not a huge deal to get information later.