A study by IIT Delhi reveals that vehicle speeds had increased 11am onwards during the first phase of the odd-even scheme. The maximum increase recorded was 9%.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/odd-even-was-little-use-says-iit-study
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/odd-even-numbered-cars
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/indian-institute-technology-iit
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/two-wheelers
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-road-research-institute-crri
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment-pollution-control-authority-epca