"Shine Bright Like a Diamond," Cyclists... (days are getting shorter)

September and October are the very best months to be outside here in Colorado.  While it remains warm, it is not intensely hot.   The leaves change colors, there is that crisp cool snap in the air when you wake in the morning, it rarely rains or storms, and it is predictably sunny and gorgeous almost daily.    

It is, therefore, the ideal time of year to bike commute!  (ahem, #ridemoredriveless).

However, commuting this time of year means something else: the loss of daylight on both ends, with later sunrise and an earlier sunset, and sometimes it can change quite a bit from one day to the next.  (On average in September, the sun rises 1 minute later each morning and sets 2 minutes earlier each evening).  September 1 sunrise was 6:28am, whereas by September 30, it does not rise until 6:55am.  September 1 sunset was 7:31pm, but by September 30 it will set at 6:44pm.  

In other words, if you are leaving your office around 5:30-6pm to start your ride home, these daily changes require different lighting considerations each trip.    

So- as the calendar ticks towards the shortest days of the year, bike commuters need to increase their level of preparedness when it comes to lighting and visibility.  One day a ride home at 5pm may be in total daylight… yet just a week later, it creeps into dusk … even a slight delay at the office can mean the difference between riding home in the dusk versus the dark. 

For these reasons, let’s talk about what the law requires of cyclists when it comes to being seen.

In a nutshell: cyclists must have a white light on the front and a red light or reflector on the back, at least 30 minutes before sunset, through 30 minutes after sunrise.  Cyclists must also be visible/reflective from the sides.  The same is true when visibility is low, for example on cloudy or hazy days or during times of fog.  

For your reference, here are the Colorado statutes on point: (most states are similar or identical on this issue):

§ 42-4-221. Bicycle and personal mobility device equipment

… (2)

Every bicycle, … in use at the times described in section 42-4-204 (see below) shall be equipped with a lamp on the front emitting a white light visible from a distance of at least five hundred feet to the front.


Every bicycle, … shall be equipped with a red reflector of a type approved by the department, which shall be visible for six hundred feet to the rear when directly in front of lawful lower beams of head lamps on a motor vehicle.


Every bicycle, … when in use at the times described in section 42-4-204 shall be equipped with reflective material of sufficient size and reflectivity to be visible from both sides for six hundred feet when directly in front of lawful lower beams of head lamps on a motor vehicle or, in lieu of such reflective material, with a lighted lamp visible from both sides from a distance of at least five hundred feet.

§ 42-4-204. When lighted lamps are required

(1) Every vehicle upon a highway within this state, between sunset and sunrise and at any other time when, due to insufficient light or unfavorable atmospheric conditions, persons and vehicles on the highway are not clearly discernible at a distance of one thousand feet ahead, shall display lighted lamps and illuminating devices as required by this article for different classes of vehicles, subject to exceptions with respect to parked vehicles… 

It is not likely that a cyclist would be pulled over by law enforcement and cited for lack of appropriate lighting as a stand-alone issue. (But then again -See below)... However, a lack of lighting and reflective gear can be a contributing factor in a crash; for example if a motorist cannot see a cyclist and makes a left turn directly into the path of the oncoming cyclist –then the cyclist be found at fault, either in whole or in part.

The reality is, it pays for cyclists to be seen.  Many riders have adopted the practice of riding with blinking lights during daytime and nighttime hours, in the hopes of being seen and therefore avoiding crashes with motorists.  Whatever your philosophy about lights during daylight hours – be sure you have lights/reflectors/reflective gear during those dusk/dark hours!  Failure to pack lights means you will not be able to see your path clearly, but even worse, other road users will not be able to see you!

Lack of proper lighting can provide the basis for a valid traffic stop –so law enforcement could plausibly pull a cyclist over for riding at night without lights, ask for their ID, and check for –say – outstanding warrants (just like a defective headlamp in your car could provide a basis for a traffic stop). For example: