Evaluation of Get Ready Get Thru the Vines

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Leonard, G.S.; Wright, K.C. 2011 Evaluation of Get Ready Get Thru the Vines. Lower Hutt, N.Z.: GNS Science. GNS Science report 2011/01 21 p.

Abstract: Hastings District Council organised a ‘Get Ready Get Thru The Vines: Walk the tsunami evacuation routes’ day from 10am to 4pm on December 5th, 2010 in Haumoana, Clifton, and Te Awanga. A siren test was also conducted. GNS Science was contracted to help evaluate the effectiveness of (a) the four evacuation routes and (b) the public alerting siren and message. Two studies were conducted: (1) a ‘participant’ survey for the public walking through each route and (2) an ‘observer’ survey conducted at a variety of distances from each siren test. This report provides a rapid bullet-point summary of key results. Forty-nine completed ‘participant’ surveys were returned allowing indicative interpretations for the larger community; the margin of error for this survey is ±14%. Forty eight ‘observer’ forms were completed for the siren test. The majority of public participants heard about the event from the flyer drop to letterboxes or the newspaper. Four evacuation routes were trialled by the public. Elephant Hill may generally be a faster route (average 15 minutes), compared to The Downs (average 29 minutes). The average walking time across all routes was 22 minutes. In general participants indicated that the routes could be used in the dark with a torch, in all weather, but with some mobility impaired people finding them difficult or slower. There were no significant cross-tabulations (such as evacuee age) to travel time. Participants indicated a range of welfare items they would like to take with them and have at the safe location, especially food and water. Pets were identified as an issue. Many people brought children to the event. Ninety percent of respondents were travelling in groups, which ranged in size from two to seven people. Assume the siren’s minimum effective range is about 180m (i.e. it may be effective further away, but is particularly effective within 180m) for people who are not hearing impaired, are outdoors, on a calm day, without significant ambient noise. In contrast, the public alerting message as it stands (see recommendation 2) has a minimum effective range of 120m. An effective range for the alerting message and especially the siren may be up to 300m, depending on wind conditions and the terrain between the siren and the persons needing to hear it. It is recommended that the levels of the siren and message are balanced so they have the same breadth of bass vs. treble, and same peak dB. We tested the siren with observers, who either knew the exact time and location of test, and also with public participants, who at least knew something related to Civil Defence was happening; tests of other scenarios should ideally also be undertaken, including indoors and during bad weather. (auth)