It is easy to assume that drivers have good eyesight and are paying attention, but often neither of these is true. Even when they are, cyclists wearing dark clothing against a dark background are simply harder to see, especially at night in the rain, so good lights and bright, reflective clothing all help you be seen and thus avoid accidents.
The rucksack cover is from Polaris, the tyres are Schwalbe Marathon Plus (which are also great for puncture resistance) and there are some tyre valve lights fitted.
These photos were taken with a light source shining from the camera to simulate car headlights; please remember that if two cyclists were approaching from opposite directions on an ill-lit cycle path, and they both had no lights but lots of hi-viz clothing, they may well not see each other and crash, so good lights are essential.
When the crank bolts come loose, the mating surfaces involved get damaged;in the case of alloy cranks, the cranks themselves bear the brunt of it, as they are softer than the steel of the bottom bracket, but, even with alloy cranks, the bottom bracket itself can also get damaged by the cranks if you cycle for more than a short distance with the cranks loose.
I saw a customer today whose crank bolts (the bolts that attach the crank arms to the bottom bracket, had come loose, in this case on both sides. This is quite an expensive repair relative to the value of the bike, at around £40, as the bottom bracket had also been damaged, and it may be enough to make the repair uneconomic, subject to the customer’s input. I’d recommend that crank bolts be checked when the bike is brand new, before riding, after doing fifty miles on a new bike, then periodically every fifty hours of use after that. This applies to all cranks, including square taper, three-piece BMX cranks, and two-piece cranks. And if you ever notice any looseness in the cranks that may be from a loose bolt, stop riding the bike straight away and get it tightened.