South Perth Rouleurs

Ride Routes 11th – 17th July

The shortest day of the year past us by almost two and a half weeks ago (June 21st) and so technically, the days are getting longer. From that date to now, we have 6 minutes more daylight to play with, but as early morning cyclists, it is not quite what it seems. All of that extra light has come at the end of the day and we won’t see significant changes to the sunrise time until after July.

Twilight is a term that is used to define that period of time between night and day where there is still light outside but the sun is below the horizon. This usually gives the most spectacular skies where the light refracts off the upper atmosphere. After the 2022 volcano at Tonga, so much particulate was ejected into the upper atmosphere that we had the best sunrises and sunsets for months.

Civil Twilight refers to a particular time during twilight where that is enough natural sunlight that artificial light may not be required to carry out outdoor activities. Technically, it is when the sun is 6 deg below the horizon. Civil Twilight is also estimated on any of the sunrise/sunset websites and so we can see when we won’t need lights for our 5:30am earlybird rides. At this point in time it will be the 1st of October, so still a few months away.

This is really just a lot of technical guff for me to say that you will need lights on the early rides and to reiterate our policy of lights in group rides.

Our ride etiquette insists that all lights be kept on solid mode only during a group ride. With the early rides often going through areas that are not well lit, the contrast of the lights to a rider can be quite intense. If your light is advertised that it is so strong that it can burn out retinas at 200m, then please find a lower strength mode. If that light is flashing, then the distraction to riders can be quite dangerous. On top of that, the increase of moisture over winter can mean that glasses get fogged up or have road spray on them. When the light hits this, it refracts to make the effect 10 times worse.

Rides like the Thursday earlybird are quite fast at close quarters, so riders need to have their wits about them or accidents happen. Being distracted by flashing lights does increase the risk of a rider misjudging a manoeuvre.

The Garmin Varia rear light seems to be a very popular addition to the local peloton in recent years. This device senses vehicles coming from behind and can schematically display them on your head unit so you can see if something is approaching. On top of that, the rear light will then flash to attract attention. There is a “Peloton” mode on the Varia and this puts the light onto solid but still will flash if it detects a vehicle coming from behind. Technically, it flashes in a less aggressive way than normal mode, but it still flashes. It is also meant to sense the closing speed differential between the rider and the vehicle it detects. This means that it shouldn’t flash when riding in a group until it senses a vehicle with a greater speed differential (10-20 kph). Unfortunately, it can still trigger if bikes are moving around at different speeds within a group. Rolling through, for example, or catching up to a group can trigger enough of a speed differential.

So, technically, the Garmin Varia and other similar devices do still flash while people are riding in the group. Yes, they flash less aggressively, but they do still flash and can cause the same distraction that other flashing lights do. There is no solid only mode on the Garmin device as they are either on or off. We are not looking at a blanket ban on these devices as it is a clear example of technology changes out-stripping policy, so the committee will need further discussion. However, riders need to be aware of what their light is doing. As these are a rear light, the majority of the time, the offending rider would not even know. So think about the other riders in the group, especially if the roads are wet and give extra space to each other so that you have a bit of a buffer for reaction time.

https://southperthrouleurs.com.au/2026/07/09/ride-routes-11th-17th-july-3/