Data on accidents involving cyclists can be found here: https://nehody.cdv.cz/statistics.php?h=zx. Some of the towns and cities perform their own monitoring on dangerous spots, such as the Capital of Prague which uses a website https://app.iprpraha.cz/apl/app/mapa-online/?service[]=21, or the city of Brno https://data.brno.cz/.
However, the data on cyclists' safety and the quality of cycling infrastructure are hardly used in the Sustainable Urban Mobility Plans in the CR (the analytical section sometimes works with the data, but without any reflection into the implementation section).