Versions of Iowa Code 321.314 - When signal required on LawServer 2023 Iowa Code 321.314 – When signal required 2022 Iowa Code 321.314 – When signal required 2020 Iowa Code 321.314 – When signal required 2018 Iowa Code 321.314 – When signal required 2016 Iowa Code 321.314 – When signal required 2014 Iowa Code 321.314 – When signal required. 2009 Iowa Code 321.314 – When signal required