def determine_vehicle_pos(left_line_start, right_line_start):
    """
    Calculates the deviation of the vehicle center in meters.

    :param left_line_start: The current position of the left lane
    :param right_line_start: The current position of the right lane
    :return: The vehicle position relative to the lines
    """

    LEFT_LINE_ZERO = 203
    RIGHT_LINE_ZERO = 1091
    PIXELS2METERS = 1.33 / 700

    ideal_pos = LEFT_LINE_ZERO + (RIGHT_LINE_ZERO - LEFT_LINE_ZERO)/2
    true_pos = left_line_start + (right_line_start - left_line_start)/2

    diff_pix = ideal_pos - true_pos
    diff_meters = diff_pix * PIXELS2METERS

    return diff_meters