# Title 40

## SECTION 1037.515

### 1037.515 Determining CO2 emissions to show compliance for trailers.

§ 1037.515 Determining CO2 emissions to show compliance for trailers.This section describes a compliance approach for trailers that
is consistent with the modeling for vocational vehicles and
tractors described in § 1037.520, but is simplified consistent with
the smaller number of trailer parameters that affect CO2 emissions.
Note that the calculated CO2 emission rate, *e*CO2, is
equivalent to the value that would result from running GEM with the
same input values.

(a) *Compliance equation.* Calculate CO2 emissions for
demonstrating compliance with emission standards for each trailer
configuration.

(1) Use the following equation:

Where:*C*i = constant values for calculating CO2 emissions from this regression equation derived from GEM, as shown in Table 1 of this section. Let

*C*5 = 0.988 for trailers that have automatic tire inflation systems with all wheels, and let

*C*5 = 0.990 for trailers that have tire pressure monitoring systems with all wheels (or a mix of the two systems); otherwise, let

*C*5 1.

*TRRL*= tire rolling resistance level as specified in paragraph (b) of this section. Δ

*C*d

*A*= the Δ

*C*d

*A*value for the trailer as specified in paragraph (c) of this section.

*WR*= weight reduction as specified in paragraph (d) or (e) of this section.

Table 1 of § 1037.515 - Regression Coefficients for Calculating CO2 Emissions

Trailer category | C1 | C2 | C3 | C4 |
---|---|---|---|---|

Long dry box van | 76.1 | 1.67 | −5.82 | −0.00103 |

Long refrigerated box van | 77.4 | 1.75 | −5.78 | −0.00103 |

Short dry box van | 117.8 | 1.78 | −9.48 | −0.00258 |

Short refrigerated box van | 121.1 | 1.88 | −9.36 | −0.00264 |

(2) The following is an example for calculating the mass of CO2
emissions, *e*CO2, from a long dry box van that has a tire
pressure monitoring system for all wheels, an aluminum suspension
assembly, aluminum floor, and is designated as Bin IV:

*C*1 = 76.1

*C*2 = 1.67

*TRRL*= 4.6 kg/tonne

*C*3 = -5.82 Δ

*C*d

*A*= 0.7 m 2

*C*4 = -0.00103

*WR*= 655 lbs

*C*5 = 0.990

*e*CO2 = (76.1 + 1.67 + (−5.82 ·0.7) + (−0.00103 ·655)) ·0.990

*e*CO2 = 78.24 g/ton-mile

(b) *Tire rolling resistance.* Use the procedure specified
in § 1037.520(c) to determine the tire rolling resistance level for
your tires. Note that you may base tire rolling resistance levels
on measurements performed by tire manufacturers, as long as those
measurements meet this part's specifications.

(c) *Drag area.* You may use Δ*C*d*A* values
approved under § 1037.211 for device manufacturers if your trailers
are properly equipped with those devices. Determine
Δ*C*d*A* values for other trailers based on testing.
Measure *C*d*A* and determine Δ*C*d*A* values
as described in § 1037.526(a). You may use Δ*C*d*A*
values from one trailer configuration to represent any number of
additional trailers based on worst-case testing. This means that
you may apply Δ*C*d*A* values from your measurements to
any trailer models of the same category with drag area at or below
that of the tested configuration. For trailers in the short dry box
vans and short refrigerated box vans that are not 28 feet long,
apply the Δ*C*d*A* value established for a comparable
28-foot trailer model; you may use the same devices designed for
28-foot trailers or you may adapt those devices as appropriate for
the different trailer length, consistent with good engineering
judgment. For example, 48-foot trailers may use longer side skirts
than the skirts that were tested with a 28-foot trailer. Trailer
and device manufacturers may seek preliminary approval for these
adaptations. Determine bin levels based on Δ*C*d*A* test
results as described in the following table:

Table 2 of § 1037.515 - Bin Determinations for Trailers Based on Aerodynamic Test Results

[ΔCdA in m ^{2}]

If a trailer's measured ΔCdA is . . . | designate the trailer as . . . | and use the following value for ΔCdA |
---|---|---|

≤0.09 | Bin I | 0.0 |

0.10-0.39 | Bin II | 0.1 |

0.40-0.69 | Bin III | 0.4 |

0.70-0.99 | Bin IV | 0.7 |

1.00-1.39 | Bin V | 1.0 |

1.40-1.79 | Bin VI | 1.4 |

>1.80 | Bin VII | 1.8 |

(d) *Weight reduction.* Determine weight reduction for a
trailer configuration by summing all applicable values, as
follows:

(1) Determine weight reduction for using lightweight materials for wheels as described in § 1037.520(e).

(2) Apply weight reductions for other components made with light-weight materials as shown in the following table:

Table 3 of § 1037.515 - Weight Reductions for Trailers

[pounds]

Component | Material | Weight reduction (pounds) |
---|---|---|

Structure for
Suspension Assembly ^{1} |
Aluminum | 280 |

Hub and Drum (per axle) | Aluminum | 80 |

Floor
^{2} |
Aluminum | 375 |

Floor
^{2} |
Composite (wood and plastic) | 245 |

Floor Crossmembers
^{2} |
Aluminum | 250 |

Landing Gear | Aluminum | 50 |

Rear Door | Aluminum | 187 |

Rear Door Surround | Aluminum | 150 |

Roof Bows | Aluminum | 100 |

Side Posts | Aluminum | 300 |

Slider Box | Aluminum | 150 |

Upper Coupler Assembly | Aluminum | 430 |

^{1} For tandem-axle suspension
sub-frames made of aluminum, apply a weight reduction of 280
pounds. Use good engineering judgment to estimate a weight
reduction for using aluminum sub-frames with other axle
configurations.

^{2} Calculate a smaller weight
reduction for short trailers by multiplying the indicated values by
0.528 (28/53).

(e) *Off-cycle.* You may apply the off-cycle provisions of
§ 1037.610 to trailers as follows:

(1) You may account for weight reduction based on measured values instead of using paragraph (d) of this section. Quantify the weight reduction by measuring the weight of a trailer in a certified configuration and comparing it to the weight of an equivalent trailer without weight-reduction technologies. This qualifies as A to B testing under § 1037.610. Use good engineering judgment to select an equivalent trailer representing a baseline configuration. Use the calculated weight reduction in Eq. 1037.515-1 to calculate the trailer's CO2 emission rate.

(2) If your off-cycle technology reduces emissions in a way that is proportional to measured emissions as described in § 1037.610(b)(1), multiply the trailer's CO2 emission rate by the appropriate improvement factor.

(3) If your off-cycle technology does not yield emission reductions that are proportional to measured emissions, as described in § 1037.610(b)(2), calculate an adjusted CO2 emission rate for your trailers by subtracting the appropriate off-cycle credit.

(4) Note that these off-cycle provisions do not apply for trailers subject to design standards.