APPENDIX L

Metric/English Conversion Procedures

## Introduction {#introduction .HPMS-Heading-3}

The HPMS software is capable of converting HPMS files from English to
metric and vice versa when using the import process. The units are set
by selecting *Admin Tools/Change State/Year*. Once the data have been
imported into the system, the units cannot be changed. If a State
chooses to work in different units, the data must be exported and then
reimported after the units are reset.

All data are converted to metric by the HPMS software during the
submittal process, *FHWA Submittal/Send Submittal.*

The following data items are converted:

  ------------------------------------------------------------------------
  **Item No.** **Description**              **Conversion Units**
  ------------ ---------------------------- ------------------------------
  3            Reporting Units              Codes 0 (English);1 (Metric)

  11-12        LRS MPT/KMPT                 Miles - Kilometers

  30           Section Length               Miles - Kilometers

  35           Roughness (IRI)              Inches/Mile - Meters/Kilometer

  51           D (Slab Thickness)           Inches - Millimeters

  54           Lane Width                   Feet - Meters

  57           Median Width                 Feet - Meters

  59-60        Shoulder Width (Right and    Feet - Meters
               Left)                        

  63-68        Curves (6 Values)            Miles - Kilometers

  72-77        Grades (6 Values)            Miles - Kilometers

  79           Weighted Design Speed        MPH - km/h

  80           Speed Limit                  MPH - km/h
  ------------------------------------------------------------------------

## Hard Conversion {#hard-conversion .HPMS-Heading-3}

Hard conversion is accomplished via a table lookup where a current value
is converted directly to a predetermined value. In these cases, the
computed rounded values may not always be identical to the soft
conversion value. Hard conversion is used whenever possible for the
following items:

  ------------------- ---------------------------------------------------
  **Item**            **Data**

  54                  Lane Width

  59-60               Right and Left Shoulder Width

  79                  Weighted Design Speed

  80                  Speed Limit
  ------------------- ---------------------------------------------------

For current lane or shoulder widths from 0.3 meters to 5.6 meters (1
foot to 18 feet), the hard conversion value is as found in Tables L-3
(English to metric) and L-4 (metric to English) for Items 54, 59, and
60. Any current value which is less than the lower limit or greater than
the upper limit of the appropriate portion of these tables is converted
using a soft conversion (e.g., 32 feet becomes 9.8 meters).

Weighted design speed (Item 79) and speed limit (Item 80) should be
coded in multiples of 5. If coded in multiples of 5, and if within the
limits of Tables L-1 (5 to 75 miles per hour) or L-2 (10 to 120
kilometers per hour), a hard conversion is used; otherwise, a soft
conversion is made. Where there is no speed limit, code "A999" is used
for either metric or English.

## Soft Conversion {#soft-conversion .HPMS-Heading-3}

A soft conversion is a computation using the current value times a
conversion factor to produce a converted value (e.g., 13 feet x 0.3048
meter/foot = 3.9624 meters). Any computed value is then rounded to the
required number of decimal positions (e.g., 3.9624 meters becomes 4.0
meters for a 1 decimal place precision).

The following list of factors are used when making soft conversions:

  ------------------------------ ----------------- -----------------------
  **Field Units Being            **English to      **Metric to English**
  Converted**                    Metric**          

  Miles - Kilometers             1.609344          1 / 1.609344

  Feet - Meters                  0.3048            1 / 0.3048

  Inches per Mile - Meters per   1 / 63.36         63.36
  Kilometer                                        

  Inches - Millimeters           25.4              1 / 25.4

  MPH - km/h                     1.609344          1 / 1.609344
  ------------------------------ ----------------- -----------------------

Soft conversion is used on the following data items:

  ------------------------------------------------------------------------
  **Item No.**    **Description**         **Conversion Units**
  --------------- ----------------------- --------------------------------
  11-12           LRS MPT/KMPT            Miles - Kilometers

  30              Section Length          Miles - Kilometers

  35              Roughness (IRI)         Inches/Mile - Meters/Kilometer

  51              D (Slab Thickness)      Inches - Millimeters

  57              Median Width            Feet - Meters

  63-68           Curves by Class         Miles - Kilometers

  72-77           Grades by Class         Miles - Kilometers
  ------------------------------------------------------------------------

> Table L-1. Hard Conversion for Speed
>
> ENGLISH TO METRIC --- Using Factor 1.609344

+--------------------+---------------------------+---------------------+
| **MPH**            | **km/h**                  | **km/h**            |
|                    |                           |                     |
|                    | **Hard Conversion**       | **Computed**        |
+--------------------+---------------------------+---------------------+
| 5                  | **10**                    | 8.05                |
+--------------------+---------------------------+---------------------+
| 10                 | **15**                    | 16.09               |
+--------------------+---------------------------+---------------------+
| 15                 | **25**                    | 24.14               |
+--------------------+---------------------------+---------------------+
| 20                 | **30**                    | 32.19               |
+--------------------+---------------------------+---------------------+
| 25                 | **40**                    | 40.23               |
+--------------------+---------------------------+---------------------+
| 30                 | **50**                    | 48.28               |
+--------------------+---------------------------+---------------------+
| 35                 | **60**                    | 56.33               |
+--------------------+---------------------------+---------------------+
| 40                 | **65**                    | 64.37               |
+--------------------+---------------------------+---------------------+
| 45                 | **70**                    | 72.42               |
+--------------------+---------------------------+---------------------+
| 50                 | **80**                    | 80.47               |
+--------------------+---------------------------+---------------------+
| 55                 | **90**                    | 88.51               |
+--------------------+---------------------------+---------------------+
| 60                 | **100**                   | 96.56               |
+--------------------+---------------------------+---------------------+
| 65                 | **105**                   | 104.61              |
+--------------------+---------------------------+---------------------+
| 70                 | **110**                   | 112.65              |
+--------------------+---------------------------+---------------------+
| 75                 | **120**                   | 120.70              |
+--------------------+---------------------------+---------------------+
| **BOLD** indicates |                           |                     |
| what is used for   |                           |                     |
| hard conversions.  |                           |                     |
+--------------------+---------------------------+---------------------+
| Values beyond 75   |                           |                     |
| MPH and those that |                           |                     |
| are NOT multiples  |                           |                     |
| of 5 use soft      |                           |                     |
| conversions        |                           |                     |
| rounded to the     |                           |                     |
| nearest km/h.      |                           |                     |
+--------------------+---------------------------+---------------------+

> Table L-2. Hard Conversion for Speed
>
> METRIC TO ENGLISH --- Using Factor 1 / 1.609344

+----------------+-----------------------------+----------------------+
| **km/h**       | **MPH**                     | **MPH**              |
|                |                             |                      |
|                | **Hard Conversion**         | **Computed**         |
+----------------+-----------------------------+----------------------+
| 10             | **5**                       | 6.21                 |
+----------------+-----------------------------+----------------------+
| 15             | **10**                      | 9.32                 |
+----------------+-----------------------------+----------------------+
| 20             | **10**                      | 12.43                |
+----------------+-----------------------------+----------------------+
| 25             | **15**                      | 15.53                |
+----------------+-----------------------------+----------------------+
| 30             | **20**                      | 18.64                |
+----------------+-----------------------------+----------------------+
| 35             | **20**                      | 21.75                |
+----------------+-----------------------------+----------------------+
| 40             | **25**                      | 24.85                |
+----------------+-----------------------------+----------------------+
| 45             | **30**                      | 27.96                |
+----------------+-----------------------------+----------------------+
| 50             | **30**                      | 31.07                |
+----------------+-----------------------------+----------------------+
| 55             | **35**                      | 34.18                |
+----------------+-----------------------------+----------------------+
| 60             | **35**                      | 37.28                |
+----------------+-----------------------------+----------------------+
| 65             | **40**                      | 40.39                |
+----------------+-----------------------------+----------------------+
| 70             | **45**                      | 43.50                |
+----------------+-----------------------------+----------------------+
| 75             | **45**                      | 46.60                |
+----------------+-----------------------------+----------------------+
| 80             | **50**                      | 49.71                |
+----------------+-----------------------------+----------------------+
| 85             | **55**                      | 52.82                |
+----------------+-----------------------------+----------------------+
| 90             | **55**                      | 55.92                |
+----------------+-----------------------------+----------------------+
| 95             | **60**                      | 59.03                |
+----------------+-----------------------------+----------------------+
| 100            | **60**                      | 62.14                |
+----------------+-----------------------------+----------------------+
| 105            | **65**                      | 65.24                |
+----------------+-----------------------------+----------------------+
| 110            | **70**                      | 68.35                |
+----------------+-----------------------------+----------------------+
| 115            | **70**                      | 71.46                |
+----------------+-----------------------------+----------------------+
| 120            | **75**                      | 74.56                |
+----------------+-----------------------------+----------------------+
| **BOLD**       |                             |                      |
| indicates what |                             |                      |
| is used for    |                             |                      |
| hard           |                             |                      |
| conversions.   |                             |                      |
+----------------+-----------------------------+----------------------+
| Values beyond  |                             |                      |
| 10 km/h,       |                             |                      |
| beyond         |                             |                      |
| 120 km/h and   |                             |                      |
| those that are |                             |                      |
| NOT multiples  |                             |                      |
| of 5 use soft  |                             |                      |
| conversions    |                             |                      |
| rounded to the |                             |                      |
| nearest MPH.   |                             |                      |
+----------------+-----------------------------+----------------------+

Table L-3. Hard Conversion for Length

> ENGLISH TO METRIC --- Using Factor 0.3048

+--------------+------------+----------------------+-----------------+
|              | **Feet**   | **Meters**           | **Meters**      |
|              |            |                      |                 |
|              |            | **Hard Conversion**  | **Computed**    |
+==============+============+======================+=================+
| Lane Width   | 6          | **1.8**              | 1.83            |
+--------------+------------+----------------------+-----------------+
|              | 7          | **2.1**              | 2.13            |
+--------------+------------+----------------------+-----------------+
|              | 8          | **2.4**              | 2.44            |
+--------------+------------+----------------------+-----------------+
|              | 9          | **2.7**              | 2.74            |
+--------------+------------+----------------------+-----------------+
|              | 10         | **3.0**              | 3.05            |
+--------------+------------+----------------------+-----------------+
|              | 11         | **3.3**              | 3.35            |
+--------------+------------+----------------------+-----------------+
|              | 12         | **3.6**              | 3.66            |
+--------------+------------+----------------------+-----------------+
|              | 13         | **3.9**              | 3.96            |
+--------------+------------+----------------------+-----------------+
|              | 14         | **4.2**              | 4.27            |
+--------------+------------+----------------------+-----------------+
|              | 15         | **4.5**              | 4.57            |
+--------------+------------+----------------------+-----------------+
|              | 16         | **4.8**              | 4.88            |
+--------------+------------+----------------------+-----------------+
|              | 17         | **5.2**              | 5.18            |
+--------------+------------+----------------------+-----------------+
|              | 18         | **5.5**              | 5.49            |
+--------------+------------+----------------------+-----------------+
| Shoulder     | 1          | **0.3**              | 0.30            |
| Width        |            |                      |                 |
+--------------+------------+----------------------+-----------------+
|              | 2          | **0.6**              | 0.61            |
+--------------+------------+----------------------+-----------------+
|              | 3          | **0.9**              | 0.91            |
+--------------+------------+----------------------+-----------------+
|              | 4          | **1.2**              | 1.22            |
+--------------+------------+----------------------+-----------------+
|              | 5          | **1.5**              | 1.52            |
+--------------+------------+----------------------+-----------------+
|              | 6          | **1.8**              | 1.83            |
+--------------+------------+----------------------+-----------------+
|              | 7          | **2.1**              | 2.13            |
+--------------+------------+----------------------+-----------------+
|              | 8          | **2.4**              | 2.44            |
+--------------+------------+----------------------+-----------------+
|              | 9          | **2.7**              | 2.74            |
+--------------+------------+----------------------+-----------------+
|              | 10         | **3.0**              | 3.05            |
+--------------+------------+----------------------+-----------------+
|              | 11         | **3.3**              | 3.35            |
+--------------+------------+----------------------+-----------------+
|              | 12         | **3.6**              | 3.66            |
+--------------+------------+----------------------+-----------------+
| **BOLD**     |            |                      |                 |
| indicates    |            |                      |                 |
| what is used |            |                      |                 |
| for hard     |            |                      |                 |
| conversions. |            |                      |                 |
+--------------+------------+----------------------+-----------------+
| Values not   |            |                      |                 |
| shown for    |            |                      |                 |
| the item of  |            |                      |                 |
| interest are |            |                      |                 |
| soft         |            |                      |                 |
| converted    |            |                      |                 |
| and rounded  |            |                      |                 |
| to the       |            |                      |                 |
| nearest      |            |                      |                 |
| tenth of a   |            |                      |                 |
| meter.       |            |                      |                 |
+--------------+------------+----------------------+-----------------+

Table L-4. Hard Conversion for Length

#  METRIC TO ENGLISH --- Using Factor 1 / 0.3048

+-------------+--------------+--------------------+-------------------+
|             | **Meters**   | **Feet Hard        | **Feet Computed** |
|             |              | Conversion**       |                   |
+=============+==============+====================+===================+
| Lane Width  | 1.7          | **6**              | 5.57              |
|             |              |                    |                   |
|             | 1.8          | **6**              | 5.90              |
|             |              |                    |                   |
|             | 1.9          | **6**              | 6.23              |
+-------------+--------------+--------------------+-------------------+
|             | 2.0          | **7**              | 6.56              |
|             |              |                    |                   |
|             | 2.1          | **7**              | 6.89              |
|             |              |                    |                   |
|             | 2.2          | **7**              | 7.21              |
+-------------+--------------+--------------------+-------------------+
|             | 2.3          | **8**              | 7.54              |
|             |              |                    |                   |
|             | 2.4          | **8**              | 7.87              |
|             |              |                    |                   |
|             | 2.5          | **8**              | 8.20              |
+-------------+--------------+--------------------+-------------------+
|             | 2.6          | **9**              | 8.52              |
|             |              |                    |                   |
|             | 2.7          | **9**              | 8.85              |
|             |              |                    |                   |
|             | 2.8          | **9**              | 9.18              |
+-------------+--------------+--------------------+-------------------+
|             | 2.9          | **10**             | 9.51              |
|             |              |                    |                   |
|             | 3.0          | **10**             | 9.84              |
|             |              |                    |                   |
|             | 3.1          | **10**             | 10.16             |
|             |              |                    |                   |
|             | 3.2          | **10**             | 10.49             |
+-------------+--------------+--------------------+-------------------+
|             | 3.3          | **11**             | 10.82             |
|             |              |                    |                   |
|             | 3.4          | **11**             | 11.15             |
|             |              |                    |                   |
|             | 3.5          | **11**             | 11.48             |
+-------------+--------------+--------------------+-------------------+
|             | 3.6          | **12**             | 11.80             |
|             |              |                    |                   |
|             | 3.7          | **12**             | 12.13             |
|             |              |                    |                   |
|             | 3.8          | **12**             | 12.46             |
+-------------+--------------+--------------------+-------------------+
|             | 3.9          | **13**             | 12.79             |
|             |              |                    |                   |
|             | 4.0          | **13**             | 13.11             |
|             |              |                    |                   |
|             | 4.1          | **13**             | 13.44             |
+-------------+--------------+--------------------+-------------------+
|             | 4.2          | **14**             | 13.77             |
|             |              |                    |                   |
|             | 4.3          | **14**             | 14.10             |
|             |              |                    |                   |
|             | 4.4          | **14**             | 14.43             |
+-------------+--------------+--------------------+-------------------+
|             | 4.5          | **15**             | 14.75             |
|             |              |                    |                   |
|             | 4.6          | **15**             | 15.08             |
|             |              |                    |                   |
|             | 4.7          | **15**             | 15.41             |
+-------------+--------------+--------------------+-------------------+
|             | 4.8          | **16**             | 15.74             |
|             |              |                    |                   |
|             | 4.9          | **16**             | 16.07             |
|             |              |                    |                   |
|             | 5.0          | **16**             | 16.39             |
+-------------+--------------+--------------------+-------------------+
| Lane Width  | 5.1          | **17**             | 16.72             |
|             |              |                    |                   |
| (continued) | 5.2          | **17**             | 17.05             |
|             |              |                    |                   |
|             | 5.3          | **17**             | 17.38             |
+-------------+--------------+--------------------+-------------------+
|             | 5.4          | **18**             | 17.70             |
|             |              |                    |                   |
|             | 5.5          | **18**             | 18.03             |
|             |              |                    |                   |
|             | 5.6          | **18**             | 18.36             |
+-------------+--------------+--------------------+-------------------+
| Shoulder    | 0.3          | **1**              | 0.98              |
| Width       |              |                    |                   |
|             | 0.4          | **1**              | 1.31              |
+-------------+--------------+--------------------+-------------------+
|             | 0.5          | **2**              | 1.64              |
|             |              |                    |                   |
|             | 0.6          | **2**              | 1.97              |
|             |              |                    |                   |
|             | 0.7          | **2**              | 2.30              |
+-------------+--------------+--------------------+-------------------+
|             | 0.8          | **3**              | 2.62              |
|             |              |                    |                   |
|             | 0.9          | **3**              | 2.95              |
|             |              |                    |                   |
|             | 1.0          | **3**              | 3.28              |
+-------------+--------------+--------------------+-------------------+
|             | 1.1          | **4**              | 3.61              |
|             |              |                    |                   |
|             | 1.2          | **4**              | 3.93              |
|             |              |                    |                   |
|             | 1.3          | **4**              | 4.26              |
+-------------+--------------+--------------------+-------------------+
|             | 1.4          | **5**              | 4.59              |
|             |              |                    |                   |
|             | 1.5          | **5**              | 4.92              |
|             |              |                    |                   |
|             | 1.6          | **5**              | 5.25              |
+-------------+--------------+--------------------+-------------------+
|             | 1.7          | **6**              | 5.57              |
|             |              |                    |                   |
|             | 1.8          | **6**              | 5.90              |
|             |              |                    |                   |
|             | 1.9          | **6**              | 6.23              |
+-------------+--------------+--------------------+-------------------+
|             | 2.0          | **7**              | 6.56              |
|             |              |                    |                   |
|             | 2.1          | **7**              | 6.89              |
|             |              |                    |                   |
|             | 2.2          | **7**              | 7.21              |
+-------------+--------------+--------------------+-------------------+
|             | 2.3          | **8**              | 7.54              |
|             |              |                    |                   |
|             | 2.4          | **8**              | 7.87              |
|             |              |                    |                   |
|             | 2.5          | **8**              | 8.20              |
+-------------+--------------+--------------------+-------------------+
|             | 2.6          | **9**              | 8.52              |
|             |              |                    |                   |
|             | 2.7          | **9**              | 8.85              |
|             |              |                    |                   |
|             | 2.8          | **9**              | 9.18              |
+-------------+--------------+--------------------+-------------------+
|             | 2.9          | **10**             | 9.51              |
|             |              |                    |                   |
|             | 3.0          | **10**             | 9.84              |
|             |              |                    |                   |
|             | 3.1          | **10**             | 10.16             |
|             |              |                    |                   |
|             | 3.2          | **10**             | 10.49             |
+-------------+--------------+--------------------+-------------------+
|             | 3.3          | **11**             | 10.82             |
|             |              |                    |                   |
|             | 3.4          | **11**             | 11.15             |
|             |              |                    |                   |
|             | 3.5          | **11**             | 11.48             |
+-------------+--------------+--------------------+-------------------+
| Shoulder    | 3.6          | **12**             | 11.80             |
| Width       |              |                    |                   |
|             | 3.7          | **12**             | 12.13             |
| (continued) |              |                    |                   |
|             | 3.8          | **12**             | 12.46             |
+-------------+--------------+--------------------+-------------------+
| **BOLD**    |              |                    |                   |
| indicates   |              |                    |                   |
| what is     |              |                    |                   |
| used for    |              |                    |                   |
| hard        |              |                    |                   |
| c           |              |                    |                   |
| onversions. |              |                    |                   |
+-------------+--------------+--------------------+-------------------+
| Values not  |              |                    |                   |
| shown for   |              |                    |                   |
| the item of |              |                    |                   |
| interest    |              |                    |                   |
| are soft    |              |                    |                   |
| converted   |              |                    |                   |
| and rounded |              |                    |                   |
| to the      |              |                    |                   |
| nearest     |              |                    |                   |
| foot.       |              |                    |                   |
+-------------+--------------+--------------------+-------------------+