Railroad Quiet Zones

Boulder County’s and BNSF’s work is complete and the crossings along the Diagonal Highway have been officially designated as Quiet Zone compliant by the Federal Railways Administration (FRA) and the State of Colorado Public Utilities Commission (PUC). A quiet zone crossing does not mean that train horns will completely cease at that crossing. The train conductor will still have the discretion of sounding the horn if they believe there is a safety hazard.

Official Quiet Zone Crossings in Unincorporated Boulder County:

  • 2nd Avenue in Niwot
  • Niwot Road
  • Monarch Road
  • 63rd Street
  • 55th Street
  • Jay Road
  • Independence Road

Longmont, Boulder, Louisville, Lafayette, Broomfield and Westminster are also working on creating Quiet Zone crossings within their city limits.

Introduction & Background

Boulder County received a $1.4 million grant from the Denver Regional Council of Governments (DRCOG) to implement quiet zones along the SH 119/Longmont Diagonal corridor. The improvements and funding are an element of the FasTracks program for the Northwest rail corridor. Quiet zones are safety improvements to roads that cross railroad tracks, and, when implemented, eliminate the requirement for train horn use at those crossings.

Due to funding constraints, the county was not able construct quiet zones improvements at all crossing locations in unincorporated Boulder County along the Diagonal Highway. Additional crossings will be evaluated as funding becomes available.

What is a Quiet Zone?

Since they first started rolling down the tracks, trains have sounded horns or whistles in advance of crossings as a universal safety precaution. Until recently, sounding horns was at the discretion of the train conductor, but in 2005 the Federal Railroad Administration (FRA) mandated that locomotive horns be sounded in advance of all public highway-rail crossings for a minimum of 15 seconds and a maximum of 20 seconds. The minimum volume level for horns is 96 decibels with a maximum of 110 decibels. This rule was established to address increased incidents at rail crossings.

The FRA has also provided an option to reduce train horn noise by creating the opportunity to establish quiet zones. Generally, these improvements include some combination of improved crossing arms, curbing and medians to prevent vehicles from going around gates, improved communication circuitry between the tracks, the train and the crossing arms, and in some cases localized “wayside” horns at the crossings.

The cost of a quiet zone can range significantly depending on the specific characteristics of the road and crossing, but commonly ranges from $250,00 to $500,000 per crossing. Read the conceptual cost evaluation. In order to be effective, all crossings within 1/4 mile of each other must be addressed in order to be designated as a quiet zone.

Establishing a Quiet Zone

Only local governments or public agencies may establish a quiet zone. Local governments must work in cooperation with the railroad that owns the track (Burlington Northern Santa Fe (BNSF)), the FRA, the Colorado Public Utilities Commission (PUC), and the Colorado Department of Transportation (CDOT) to assess the risk of collision at each potential quiet zone crossing. Even if a quiet zone is created and approved, train engineers have no legal duty to sound the horn, but may exercise discretion during emergency situations (i.e., the presence of a vehicle or person on the track).

Previous Meetings:

Feasibility Study

Map of Proposed Quiet Zone Locations

Railroad crossing quiet zone map of implementation locationsContact Information

  • Andrew Barth – Communications – 303-441-1032 or email

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