$builder->join('pivot_table', function($join){
        $join->on('vehicle.id','=','pivot_table.model_id')
            ->on('pivot.model_type', Vehiculo::class  );
    })->select('vehicle.*',pivot_table.*)->get();

$builder->join('pivot_table', function($join){
        $join->on('vehicle.id','=','pivot_table.model_id')
            ->on('pivot.model_type', 'like' , '%Vehiculo%');
    })->select('vehicle.*',pivot_table.*)->get();