Study from south Florida Universtiy for FDOT (Florida Dept of Transport) in the Tampa area.
88 per cent of cyclists observe laws during day, 87 percent at night. 85 per cent of drivers observe laws at nigh. Not enough night driving to include in study,
Infrastructure and bad drivers reason for law breaking.
Link
http://www.fdot.gov/research/Completed_Proj/Summary_SF/FDOT-BDV25-977-13-rpt.pdf