Navistar International Corp. Chief Executive Troy Clarke has a message for tech entrepreneur Elon Musk: There will be more electric trucks on the road by 2025 from Navistar than semi-tractors from Musk’s Tesla Inc. It’s all about familiarity, comfort and established customer base. Navistar’s International brand already holds 11% of the market for trucks in the heaviest Class 8 weight segment, according to research firm Statista.