The screen shot below illustrates the quiet zone with crossings at 3rd, 7th, 8th, and 9^th Streets with no supplementary safety measures (SSMs).  The Quiet Zone Risk Index is not lower than either the Nationwide Significant Risk Threshold or the Risk Index with Horns; therefore a quiet zone cannot be established without implementing SSMs. 

The Quiet Zone Risk Index is most cost-effectively lowered by implementing SSMs at the crossings with the highest risk level.  Installation of medians with reflective traffic channelization devices (coded “12” in the “SSM” column below) at the 3rd Street and 7th Street crossings lowers the Quiet Zone Risk Index to an acceptable level for establishing a quiet zone under Federal Railroad Administration rules.