are dedicated to surface transportation security. (b) Deployment Explosives detection canine teams trained and certified under subsection (a) shall be deployed to surface transportation assets in a risk-based manner, to address specific threats, or on an as-needed basis. Such teams may also be used on a more limited basis for the security of other transportation modes and to support other homeland security missions, as determined appropriate by the Secretary of Homeland Security. (c) Authorization of appropriations There is authorized to be appropriated to carry out this section— (1) $23,900,000 for fiscal year 2018