const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck' ];

const tally = data.reduce((obj, item) => {
  if(!obj[item]) {
    obj[item] = 0;
  }
  obj[item]++;
  return obj
}, {});

console.log(tally);