Possible Clues:

• Put off by people on motorway showing single-mindedness
• The end put to lower classes' indefatigability
• Resolve to show backbone
• Resolve to prohibit race on motorway
• Resolution to the end
• Prevent people covering busy road in grit
• Will settlement
• Decision process to prevent motorway touching country
• Firm resolve
• Put off married state, one's bound to show firmness of mind