Winter sunlight can dazzle drivers and cyclists alike. Here's what you can do to see and be seen.
Sunny winter days are a welcome respite from greyness, rain, or snow, but they carry an additional risk: blindingly bright low sun. The sun never gets high in the sky at this time of year, and it's at its lowest in the morning and late afternoon – just when you're likely to be commuting. Anyone looking east or south east on a sunny winter's morning or west or south west on a sunny winter's afternoon may be dazzled. It's worst when looking uphill into the sun.
The Highway Code, Rule 237, says: ‘If you are dazzled by bright sunlight, slow down and, if necessary, stop.’ Some drivers flat out ignore this advice and drive into spaces that they cannot clearly see. That's the main hazard for cyclists. But you also need to ensure that you can see properly, so that you can react to whatever drivers do.
Sunglasses are an obvious way to cope with low sun on a bike. Cycling glasses have more wraparound coverage, which helps stop your eyes watering in the wind, but in terms of reducing glare, any sunglasses will do.
Very dark sunglasses obscure your vision when you move from strong sunlight directly into deep shadow so they won't suit all commutes. Photochromic lenses, meanwhile, will not darken or lighten quickly enough to cope with fast changing conditions of sunlight and shade. If you're going to take your glasses on and off, you'll need master the art of resting them on your head or helmet, like road racers do. Alternatively, use glasses with lighter-coloured lenses – yellow or orange, for example. These will reduce glare without compromising your vision in shadows.
Wear a peaked cycling cap, which will fit fine under a helmet, or a peaked helmet. You've then got your own sun visor. By dipping your head towards the road, you'll pretty much eliminate the dazzle of low sun.
Dipping your head to focus on the road directly in front of you is a good way to deal with flickering light and shadow when the sun is off to one side, behind a fence or foliage. This flickering can be distractingly hypnotic otherwise.
Cyclists are not required to have daytime running lights and, most of time, will not need them. In low winter sun, however, they may be useful. Your aim is to draw attention to yourself as soon as possible, so a flashing or better yet a pulsing light will be more effective than a steady light. A rear light needs to be very bright to be visible in strong sunlight; look for one offering tens of lumens in output. The front light doesn't need to be much more powerful than this, as you won't be using it to see where you're going and so don't need 'full-beam' brightness.
Clothing colour is less of a factor when someone is looking towards you in blinding sunlight. Either you'll be silhouetted or you won't. More contrast is nevertheless good, so a bright white jacket isn't ideal. That doesn't mean that black is best. Lighting conditions change during any ride, as well as between rides, and black will be less visible in other circumstances.
Drivers are more likely to be ready to react to your presence in two circumstances. One is if you are cycling where they expect traffic in general to be, which good road positioning should ensure. The other is if you are cycling where they expect cyclists to be – not 'the gutter', but rather 'thoroughfares popular with cyclists'. A driver who has overtaken half a dozen cyclists already is more likely to expect one in that sun-glaring section of road ahead.
Whenever you're cycling in low sun conditions, be prepared to be treated like you're invisible. You might be. Irrespective of whether you have priority, assume drivers haven't seen you unless the circumstances indicate otherwise. Be ready to slow down or stop.
Drivers can be blinded by the sun in any road environment. It's just as likely to happen in town as in the country. However, the danger of a blinded driver is directly proportional to the speed they're travelling at. A driver doing 60mph travels 27 metres per second and could be right on you in the squint of an eye. A driver travelling at 20 or 30mph has a much bigger margin for error, so roads with lower speed limits are safer whenever visibility is compromised.
Low sunlight isn't a uniform problem. It's significantly worse on some sections of east- or west-facing road than others. Choosing a more circuitous route to or from work may enable you to avoid these. If not, and if you're not comfortable mixing with drivers who might ignore Highway Code Rule 237, plot your sunny winter journeys to work using routes that drivers won't or can't use. Backstreets with bollards, cycle tracks, towpaths, and bridleways can make excellent commuting routes now and at any time of year.