What have you discovered so far?
Phosphorescense and fluorescence come to mind where materials could be exposed to sunlight then concentrated with lenses and parabolic reflectors but the light would not be bright. Think taillights and warning lights rather than headlights.
Cerenkov radiation does not necessarily require electricity nor strictly chemical reactions and can be quite bright, if a bit ghastly. Typical Cerenkov sources do not seem very portable, as for headlights. The Wright brothers of aircraft fame experimented with bicycle headlights powered mechanically but biographies did not reveal their experimental
light emiting components.
@BillTre appears on a productive path with biological light sources such as the (relatively) brightly lit lures used by angler fish and certain cephlapod photophores. Biolumenescent organisms can be captured and concentrated but lumen output likely weak. Of course these involve chemical reactions.
During the 1989 Loma Prieta earthquake in Scotts Valley CA, several witnesses reported flashes of light from intense ground movements. Mechanical light not easily translated to vehicles but an interesting data point.