After more than 20 years of only mechanical brush cutting, ADOT&PF evaluated the use of herbicides to manage vegetation that interferes with line-of-sight and maintenance of the roadway. While researchers have investigated herbicide effectiveness and attenuation in more-temperate climates, little study has focused on cold regions. The purpose of this project was to measure the effectiveness and attenuation of two different selective auxin-type herbicides, 2, 4 dichlorophenoxyacetic acid (2,4-D), and 3,5,6-trichloro-2-pyridinyl acetic acid (triclopyr) in two subarctic climates; an extremely cold continental climate and a maritime climate. Conclusions from this study will aid the ADOT&PF in developing a plan for controlling vegetation along highway rights-of-way in Alaska.