Are solar roadways & glow-in-the dark footpaths the future of road safety?
- Tue, Sep 23, 2014
- Jon Scott
As local authorities start turning out the lights in their efforts to find savings, the relative safety of footpaths and roadways could take a turn for the worst. We have discussed before the importance of lighting design in reducing crime and making public spaces feel safer. Reduced lighting in areas that, during the day, might be pedestrian- and cycle-friendly, causes more cyclists and pedestrians to take to the better-lit roads, or even their cars, at night. During the hours of darkness, riding and walking on roads feels more secure, but the abandonment of unlit traffic-free zones in favour of well illuminated routes increases pressure on traffic flow systems and makes road safety a more urgent issue.
As smarter solutions develop, it appears that it is possible to light public pathways cheaply, and introduce roadway technology that could save lives as well as cash. There are a number of intelligent surfaces that can perform the same function as, and indeed improve on conventional lighting and signage. Safer conditions on pedestrian and cycle paths at night help to reduce the number of night-time road users, leading to a positive impact on road safety, and the environment.
Solar powered footpathsAt the moment, two stand-out types of solar powered footpath are in use and development, each employing different technologies. George Washington University’s Solar Walk was opened in autumn 2013. It features solar panels incorporated into an overhead trellis, and 27 slip-resistant, semi-transparent walkable tiles. The tiles contain photovoltaic technology to convert sunlight into electricity, which in turn powers the 450 LEDs that dot their borders. Combined, the tiles have an average peak capacity of 400W (the highest amount of power that can be produced in perfect conditions).
The installation is a sign that thus far single-use pathways could perform a double or even triple function: pathway; power source; light source. Further integration of technologies allow surfaces to be used in an even more efficient way, delivering and extracting power, light, and even information, all from the same square footage. In other parts of the world, a smart surface is being trialled that has a much more lo-tech feel. Local authorities in Cambridge and Fulham, UK and Gosford, Australia have opted to light pedestrian walkways with a rather magical-looking substance. The glow-in-the-dark surface is a smart coating for existing pathways. They contain special minerals that absorb UV light during the day and emit a soft glow during hours of darkness.
The manufacturers of the pathway at Christ’s Pieces park in Cambridge state that the luminosity of the pathway adjusts to compensate for the atmospheric light levels – brighter on pitch black nights, and dimmer on lighter evenings. The ‘Starpath’ is a treatment that can be directly applied to an existing surface without the need to take up the original path and re-lay it. It is sealed with water resistant material that also ensures it is non-slip in icy conditions. In a time when local authorities are reducing electricity consumption to save money, a new surface that acts as a light source and can be applied in a matter of hours seems like a very attractive option.
In Australia, the Gosford glow-in-the-dark path has been put in place as part of improvements to the railway system in the area. The expansion of railway tracks so that passenger services can overtake freight trains has not only improved public transport, but has led to the installation of innovative technology to improve night-time travel for pedestrians and cyclists. It is hoped that the measures will have a positive effect on road safety, and encourage more travellers to leave their cars at home, easing congestion on traffic-heavy routes.
In both Australia and the UK, the lighting will encourage pedestrians and cyclists to use the paths, rather than the roads, during hours of darkness. The path cannot be ‘switched off’- it is always ‘on’ in the dark, but as it won’t be using up electricity, there are no energy worries here. Fortunately, light pollution wouldn’t be a problem as this simple but clever surface only needs to emit light at a low level to be useful, and as the light is contained within the pathway there is by default no light spill.
Solar RoadwaysImage copyright © Dan Walden
Solar powered walkways that generate power to light themselves at night seem very sensible, but there are projects in development that ask even more of the surface beneath our feet or tyres. Idaho-based company Solar Roadways has been working on just such a project, developing prototypes almost literally out of their own back yard. The company's aim is to reduce carbon emissions by paving currently tarmacked surfaces with solar panels, turning a previously unproductive landmass into a renewable energy powerhouse.
The solar energy collected by the smart surface could be used to feed the grid during the day time, or even power things such as heating elements under the surface to clear ice and snow from the roads in the winter. Eventually, it might be possible to power electric cars as they drive along. This would be a huge development for electric vehicles, because with current road surfaces and charging systems, they have a limited range that precludes long-distance journeys.
The panels themselves have required some considerable engineering to make sure they can withstand the wear and tear of the highways more effectively than their asphalt counterpart. Grip has been raised as a potential problem, as driving on the strong textured glass that forms the road surface would feel quite different from controlling a vehicle on conventional road surfaces. The current projects that the creators are working on are intentionally small, making use of areas such as play grounds, private driveways and pedestrian walkways, enabling them to get the panels fully ready before taking to the roads.
Solar Roadways could also be the start of a new generation of smart highways. The creators of the project planned that the panels could carry data, and be fitted with LED indicators. These smart panels could then be programmed to display road markings, diversions around accidents, warnings of imminent bad conditions, speed limit reminders, and could even be used to form pedestrian crossing markings and for traffic control at junctions.
Taking a look towards the future in Russia and the Netherlands, concepts are forming to smarten up our highways with energy-saving, safety-improving technologies. The N329, near the Dutch city of Oss, is being updated with various innovations by engineering company Heijmans, working with interactive designer Daan Roosegaarde.
Some of the technologies have already been implemented, and some seem a little way off in feasibility terms. The simplest are things like photo-luminescent road markings that charge during the day and light up at night, and temperature-sensitive paint that forms distinctive patterns to warn drivers of icy conditions. Less straightforward are features like wind-lights, powered by the displaced air from cars as they pass, interactive lights that respond to the motion of a car passing by, and even induction coils to charge electric cars as they travel. All of these are designed to turn the focus of innovation on to the road surface, which receives precious little attention compared to the vehicles that use them.