UPDATED:
See the request received by Denver Department Of Environmental Health in late April.

The Colorado Department of Transportation released this statement to CBS4: This is one of the trade offs for any large construction project—the opportunity for a contractor to reduce the length of construction overall by doing work at night while balancing community needs and concerns. This is why the variance process is so important; so that these exact issues can be evaluated and discussed. At the same time, CDOT has provided home improvements to approximately 250 homes near the I-70 viaduct so that these homes have an extra measure of insulation against construction noise, whether day or night.