BikeMaps Blog

by Colin Ferster

OpenStreetMap (OSM) is the volunteered map of the world. Contributions are wide and diverse, from hobbyists to commercial interests. OSM spans across boundaries and allows many uses. That makes it a compelling dataset for personal, research, and commercial use!

As part of the Canadian Bikeway Comfort and Safety Classification System (Can-BICS) project, we are using OSM to map bike facilities across Canada.

Can-BICS is a system of classification for bike facilities that aligns engineering guides, open data provided by cities, and current bicycling safety and preference research into a common classification framework. We are developing queries and GIS operations to classify OSM across Canada according to Can-BICS labels.

As part of developing this classification, we collected more than 2000 ground reference points to train the classification and evaluate accuracy. We are also becoming active editors of OSM cycling data (in the spirit of leaving the campsite nicer than we found it). In the process of viewing the data, we are amazed by the extent and detail of mapping (if you contributed, thank you!!).

We put together some tips for people who want to edit bike data. For experienced editors, we have four recommendations for improving OSM bicycling data in Canada from the perspective of active transportation researchers.

Getting started

For those starting out, the best place is learnOSM. It introduces OSM, navigation, and basic editing and is well worth the time.

For mapping bicycling features, the OSM wiki has two key reference pages, and many more specific pages to explore:

• https://wiki.openstreetmap.org/wiki/Bicycle
• https://wiki.openstreetmap.org/wiki/Key:cycleway

Bike Ottawa has an excellent guide for consistently tagging bicycling features. OSM Can-BICS aligns with this coding scheme, and I use this reference in my own editing. The only limitation is for local street bikeways (which may be uncommon in Ottawa). See the recommendations section below for more about local street bikeways.

• https://github.com/BikeOttawa/OSM-Bike-Ottawa-Tagging-Guide

My experience

For contributing to bicycling data for safety research, I find myself adding tags to paths and bikeways on roads. I use OSMAnd for navigation on my smartphone (or just look at OSM in a webrowser when I'm planning a trip), and if it doesn’t match what I see on the ground, I will try to make it better! My favourite approach is to pick up a free tourist map and mark it up with a pencil while I’m riding my bike or visiting a place. There are tidier approaches, like field papers . I also refer to aerial and street level imagery from Bing Streetside or Mapillary(both have sharing agreements with OSM). Finally, I often spend some time rectifying pdf or paper maps from municipalities against OSM to find missing features.

Recommendations for improving the quality of cycling data for active transportation research

• Add surface tags to paths and trails. Surface is important for accessibility (Kay Teschke said “so many people need smooth surfaces beyond cyclists”). Yet 20% of our sample of multi-use trails was missing surface tags. Unpaved trails are great (they provide connectivity, recreation, and more), but providing surface tags on OSM will help the people who need accessible facilities find them and the information will help active transportation researchers too.
  
  

• Map separation between pedestrians and bikes using segregated=yes or separate geometry depending on the situation. Bike paths that are separated from pedestrians are a recent development in many places in Canada that are helpful where there are high volumes. They are associated with lower collision severity compared to multi-use paths.
  
  

• Map traffic calming on local street bikeways. One of the greatest challenges we faced in developing OSM Can-BICS is distinguishing local street bikeways (which have traffic calming and diversion), from shared lanes on major roads ( which have higher risks and severity of collisions)! Even a two lane residential road with a 50 km/h speed limit (first example below) is a much different experience than a greenway with traffic calming that forces traffic to slow down (second example below). We are having trouble on residential roads that are borderline. It’s helpful to map the features that make these good for riding: reduced speed limits, traffic calming features, and traffic diversion.
  
  

• Map both the good and the bad. One of my favourite things about OSM is that the mapping reflects the bicycling experience: great bike paths are seldom missing, while questionable shared lanes or sketchy painted lanes are sometimes missing. For bicycling safety research, it’s helpful to know where the terrible shared lanes on major roads are too. The danger is that this might attract people to ride there by giving it more visibility on the map. Make sure that the other road attributes are included for warning (e.g. # of lanes, speed limits, on-street parking etc.).
  
  

Anything to add? We would love to hear from you.

The University of Victoria is seeking an applicant to the Master's program in the Department of Geography interested in public health and mobility of aging adults. The applicant will work on a project to understand the micro barriers to walking or rolling for older adults in Victoria and the surrounding Capital Region. Research will include literature reviews on mobility barriers, analysis of survey data, and working with aging adults to map their mobility barriers on a new crowdsource tool under development: WalkRollMap.org. The mapping tool is being developed by the BikeMaps.org team at the University of Victoria in a new project funded by the Public Health Agency of Canada. The successful student will be supervised by Dr. Denise Cloutier and supported by Dr. Trisalyn Nelson. This position includes a $15K per year stipend ($30K in total over two years). To enquire about the position please send your cv/resume and a cover letter to trisalyn@uvic.ca, by March 12th.

by Ed Wiebe

The first thing you should know about black ice is that it’s not black.

In fact, black ice is almost completely transparent. It contains no air bubbles or cracks and that makes it look black because we see right through it to the dark road surface that lies beneath. What makes it so treacherous is that surfaces covered in black ice often look wet not icy. If you learn to look out for the common ways it can form you can avoid having your bicycle slip out from under you. Fig. 1. An icy trail early in the morning in Victoria, BC.

The classic black ice scenario is an early morning ride, under clear skies, with an air temperature just above freezing. The paved trail or street looks bare but as you turn a corner you find you’re on thin ice. Your wheels slip sideways and before you know it you’re on the ground nursing a bruised ego or worse.

I live in Victoria, BC, Canada. The winter climate here is warmer than most of Canada, but we see many days when the temperature is close to or below freezing for part of the day. This back and forth cycle of temperature across the freezing point is a key part of the recipe for black ice formation.

Watch out for the following:

• The cold seasons: from when frost starts to form in the fall until the chance of frost diminishes again in spring.

• Clear nighttime or early morning skies — but be wary on a morning when clouds are forming just before sunrise.

• Available water. This may be liquid water or high relative humidity.

• A smooth road or trail surface in a relatively open area, with a good view of the sky.

• A place where the trail or road dips, or a bridge that passes over a shallow valley.

Four ingredients

Black ice needs four basic ingredients. You’ll always find them together, though the path to a slippery surface may vary.

• A reasonably smooth surface.

• Liquid water.

• Freezing temperature at the surface.

• No wind.

In more wintry places than Victoria, you’ll be safer. When the air and ground temperature stay below freezing, there won’t be any liquid water around to freeze into black ice. Watch out for days when snow on or beside roads or paths melts briefly and then refreezes. Also, surfaces treated with road salt can refreeze as they cool further. Fig. 2. https://twitter.com/MDSHA/status/1085672137002835968

Smooth Surface

For black ice to form, a thin layer of water has to be able to cover the small bumps and irregularities in a surface. Asphalt rolled flat on roads and paths is ideal. It’s non-porous and smooth. Concrete can be smooth enough, but surfaces like sidewalks are typically roughened to reduce the risk of slipping.

Water

The water that forms black ice can fall from the sky as rain, or be directly deposited as dew or frost. It may also flow across road or paths when nearby ice and snow melts. Fig. 3. Ice on San Juan Ave in Saanich, BC.

Freezing Temperature

For ice to form on a surface the water that’s present has to be cooled to 0 °C or lower. Strangely, this can happen when the air temperature is warmer than freezing, as long as the surface itself gets cold enough. Often, we’ll encounter black ice on days when the air temperature a few degrees above freezing. Fig. 4. The long wooden trestle over Swan Creek in Saanich, BC, spans a shallow valley and a stream. Cold air pooling in the valley, a source of moisture, and radiative cooling lead to an icy surface.

How does it work?

Let’s go back to the classic scenario mentioned in the introduction. How does the surface chill to freezing if the air temperature is above 0 °C?

Radiative cooling.

The surface of the earth, like every other object in the universe, radiates energy away in the form of infrared light. At night, with no sunlight to warm it, the surface of the earth radiates energy away and cools. If there are clouds in the sky, they slow down the cooling by radiating energy downwards, but on clear nights, the temperature of the earth’s surface can drop sharply.

Fig. 5. Frost forms on surfaces where there is a clear view to the sky. The tree is a source of infrared energy and keeps nearby surfaces a bit warmer.

With a cold surface below it, air that lies near the cold ground at night also cools. When air is cooled its relative humidity increases. This can lead to dew formation and shallow layers of fog (shown below). Cold air is more dense than warmer air so the cold air tends to flow slowly to shallow depressions where it may pool. These layers of air might be only a metre or two thick. They will continue to chill throughout a clear night.

Fig. 6. Radiation fog can form in still air that chills due to radiative cooling. The lawn is a source of moisture.

Wind

If it’s windy the very cold layer at ground level won’t form. The wind will stir up the the layer of air closest to the ground and make it deeper. Wind also encourages evaporation, drying surfaces simply by moving more air past available water.

Dew and Frost

Barring wind, we’ll get a relatively cold surface under clear skies. When a surface cools to the dew point temperature of the air just above it water vapour mixed in with the air will begin to condense. This is dew. If the chilled surface reaches the freezing point the dew will freeze. Since surfaces tend to continue to cool under clear skies overnight a dewy road can become an icy hazard by sunrise.

Fig. 7. Heavy dew on a climb in Saanich, BC, Canada.

When the dew point temperature is below freezing we no longer see dew forming. Instead, water vapour crystallizes directly onto surfaces and grows into tiny separate crystals forming a white crust. This is frost. It’s more visible and rougher so frost is less dangerous to pedestrians and cyclists. Frost is also unlikely to grow on smooth ice that’s already formed. Fig. 8. Frost and some dew drops on grass.

Examples

Galloping Goose Trail southwest of the Selkirk Trestle

This paved trail lies parallel to the Gorge waterway in Victoria, BC (Fig. 1). The water is relatively warm and lies a few metres below the level of trail. The (relative!) warmth of the waterway makes it a prodigious source of water vapour. On a clear night parts of the trail are well exposed to the sky.

Lambrick Park and Nearby San Juan Avenue

Lambrick Park lies in a shallow valley, a broad open area of lawns and playing fields. The colder air that pools there on a still night can be several degrees colder than nearby higher ground. Often, if there’s no breeze, a thin layer of radiation fog forms in the park. There’s a lot of available moisture due to all that lawn. The ground below the fog is probably not below freezing because even fog is a source of energy (everything radiates infrared light), albeit a weak one. Timing is important, though. The surface below may have cooled to below freezing before the fog arrived. Fig. 9. Ice on the trail and frost on grass in Lambrick Park, Saanich, BC.

Some of the streets north of Lambrick Park (Fig. 3) run perpendicularly to the sides of the shallow Shelbourne Valley. Cold, moist air flows downslope in these areas and black ice can form in depressions. Be wary.

Wooden Trestle Bridges

Trestle bridges can be terribly icy (Fig. 4) even though they aren’t particularly smooth. In this case the water, accumulating from rain, melting snow, or condensation, gathers in the porous, ridged surfaces of the planks. Suspended above the ground the entire structure can cool to the air temperature which may be considerably below freezing. Worse still, the bridges are there to help cyclists cross waterways that run below. There is plenty of moisture around.

Summary

Important The key black ice warning sign to remember is clear skies overnight. Clouds in the sky, though cold themselves, add a source of energy for the surface. This means that surfaces under clouds at night tend not to cool below the air temperature.

Wind is also important. Even if only a light breeze, wind can keep relatively warm air moving past the surface. Wind also causes mixing. A thin cold layer can’t form. What cold air that may have otherwise flowed gently downslope toward shallow valleys is not able to pool and get still colder.
Fig. 10. A thermometer that shows when ice is possible.

Extras

Other ways for black ice to form

• Light rain on a cold enough road surface.

• Very cold air temperatures and car exhaust — lots of moisture in exhaust

• Fresh snow, compressed by human activity, that freezes solid when the temperature drops further.

Humidity and Relative Humidity

People often think that clouds are made of water vapour, but this is incorrect. Water vapour is an invisible gas; clouds are made from tiny water droplets or ice crystals that reflect light and so appear white or grey. Humidity is a measure of the water vapour, an invisible gas, that is mixed into the atmosphere. When we say the humidity is high or low we’re referring to how much water vapour is present.

Relative humidity, as you may see reported by a meteorological agency, is a way to talk about the amount of water vapour in air. There is a limit to how much water vapour the atmosphere can hold. That limit depends on the air temperature. Warm air can hold much more water vapour than cold air (there’s an exponential relationship). What’s really important for understanding dew formation or clouds and rain is the relative humidity.

If we measure how much water vapour is present and compare that, as a ratio, with the amount that could be present given the temperature of the air we get the relative humidity. If it’s raining the relative humidity will be close to 100%–that’s why it’s raining! At low relative humidities, below about 25%, we become uncomfortable because our exposed skin and the delicate membranes in our noses and throats dry too quickly.

High humidities are also uncomfortable, even dangerous, especially when it’s warm. This is because we use evaporation to cool ourselves and that’s less efficient when the relative humidity is high.

Dew point Temperature

The dew point temperature is the temperature that a sample of air would have to be cooled to for condensation of water vapour to begin. This doesn’t mean that the all of the air nearby must be chilled. Importantly, any surface in contact with the air that chills to the local dew point temperature will receive condensation.

If the dew point temperature is below freezing it’s called the frost point temperature.

The dew point is always less than the air temperature.

Ed is a Scientific Assistant in the School of Earth and Ocean Sciences at UVic who teaches and works in Climate Modelling and Meteorology. He builds and manages Victoriaweather.ca, a high resolution meteorological network on Vancouver Island.

Thank you for your interest in this position. We are now reviewing resumes.

The BikeMaps.org team is looking for a part time developer to assist with creation of a new webmap for crowdsourcing microscale barriers to walking and rolling. BikeMaps.org was launched in 2014 and is used in over 40 countries for crowdsourcing data on bicycle collisions, near misses, and hazards. Funded by the Public Health Agency of Canada (PHAC), our new tool will be similar in providing people with a mechanism for reporting barriers to safely and comfortably using our city sidewalks and pathways.

The part time developer will assist our lead developer in building the webmap, website, and visualization tools. The ideal candidate will have experience with multiple tools in the list below:

• Front-end web development experience that includes:
  • Familiarity with ReactJS
  • Demonstrated use of Typescript and/or Javascript
  • UI design and experience styling with scss or css
• Experience with Flask, Django or familiarity with Python
• Knowledge of the concepts of REST APIs
• Experience with Git and/or Github or other version control systems
• Familiar with OpenLayers, Leaflet or other JavaScript based mapping APIs
• Experience developing dynamic visualizations and charts
  
  

Competitive wages commensurate with experience. Approximately 10-15 hours per week beginning December 1, 2020. You also must be currently legally permitted to work in Canada.

The BikeMaps.org team is a collegial team of researchers who are community engaged and excited to partner with planners and health professionals. Join our team to help make streets safer and healthier!

Please send your résumé by Monday Nov 9th to:

Karen Laberee
BikeMaps.org Executive Director
klaberee@uvic.ca
250.818.7803

What would appear to many as a perfectly typical driveway was in reality a hotspot for cyclist falls and injuries.

Two cyclists reported falls near the intersection of Willingdon Avenue and Canada Way, in Burnaby, BC, Canada.

In Burnaby, B.C., Canada, near the British Columbia Institute of Technology (BCIT), at least two cyclists fell trying to access the Willingdon Urban Trail (Burnaby’s term for a multi-use path) near the intersection of Willingdon Avenue and Canada Way.

For about fifty metres north of the intersection, the path is replaced by a narrow sidewalk intended only for walking. Instead of dismounting and walking the stretch, many cyclists bypass the sidewalk using an adjacent bus lane and then return to the path using a gas station driveway.

Many cyclists use the bus lane to bypass the 50 m gap in the Willingdon multi-use path.

At least two people have fallen and were injured trying to get back onto the path at this driveway.

Driveways in Burnaby are constructed with an apron lip 4-5 cm above the road. This design standard is from mid-1969—a time when considerations for bicycles were not at the forefront of engineers’ minds.

The 1969 design standard for driveways includes a curb lip raised between 4 - 5 cm above the roadway surface, presenting a solo-bicycle fall hazard to cyclists.

The raised lip, coupled with a cyclist’s shallow angle of approach, conspired to create a fall hazard at this site. As a cyclist gently manoeuvres toward the driveway, their bicycle’s front tire could ricochet against the apron lip, leading to a fall. In the reported cases, the individuals sustained injuries severe enough to require a visit to their GP.

Armed with these incident reports, the Burnaby committee of HUB Cycling (a local cycling advocacy group) contacted the City’s engineering department. When Burnaby engineers evaluated the site and recognised the injury threat, they directed their sidewalk crews to grind down the lip to be flush with the roadway, eliminating the hazard!

The driveway apron lip was ground to be flush with the curb gutter pan, eliminating the fall hazard.

To ensure that all new driveway aprons are safely accessible by bicycle, the Burnaby committee of HUB Cycling is working with staff to update the City’s driveway design standards.

One of BikeMaps.org’s key strengths is the ability to capture incident types not recorded by other reporting systems, including falls and crashes not involving a motor vehicle. In Burnaby and cities around the world, cyclists’ incident reports are helping to make our streets safer for cycling.