--- title: "SSL Movement Index: methodology, exclusions and revision policy" description: "How the SSL Movement Index is built: definitions, sample sizes, exclusions, disclosure rules, limitations, revision policy and licence (CC BY 4.0)." url: https://safeandsecure.in/movement-index/methodology/ canonical: https://safeandsecure.in/movement-index/methodology/ updated: 2026-11-11 lang: en-IN publisher: Safe & Secure Logistics Private Limited --- SSL Movement Index # Methodology What is counted, what is left out and why, so that anyone can check the index and reproduce it. ## What it measures The volume of road freight booked through Safe & Secure Logistics (SSL) each calendar month, from SSL’s own booking register. **It is a volume index only.** It contains no freight prices, rates, charges, hire costs, margins or revenue, and no customer, consignor, consignee, vehicle or driver is identified. | Series | Definition | | --- | --- | | Tonnes moved | Sum of charged weight on every consignment booked in the month, in tonnes. | | Consignments | Number of distinct consignment notes booked in the month. | | Goods value moved | Sum of the goods value declared by the shipper on each consignment (₹ Cr). This is the value of the goods, not a freight charge. | | Packages | Sum of packages booked. | | Full-truck share | Full-truck (FTL) consignments and tonnes as a share of all consignments and tonnes with a load type of FTL or part-load. | | Corridor sub-index | Tonnes booked from one state to another (booking state → delivery state), indexed to its own Aug ’25 level. | **Index:** each month’s value ÷ its August 2025 value × 100, rounded to one decimal. It is a simple volume index with no seasonal adjustment, smoothing or re-weighting. ## Source and cleaning - Source: SSL booking register, de-duplicated by consignment number (latest entry wins). The register currently runs to 2026-03-31; only complete months are published. - De-duplication: one row per consignment number; where a consignment was entered more than once, the latest entry is used. - Excluded: any single consignment with declared goods value above ₹25 Cr, or charged weight above 100 t. Both are data-entry errors (no road consignment weighs more than a truck can carry). - **Start date:** the index begins in August 2025. From April to July 2025 full-truck bookings were not fully entered in the register (about 1,000 to 2,000 a month, against 10,000 to 13,000 from August). Starting earlier would show a false five-fold jump. ## Sample sizes | Month | Consignments | Tonnes | Full-truck | Part-load | | --- | --- | --- | --- | --- | | August 2025 | 41,882 | 64,262 | 9,851 | 31,149 | | September 2025 | 50,237 | 73,760 | 11,245 | 38,087 | | October 2025 | 38,883 | 64,083 | 10,137 | 28,023 | | November 2025 | 39,639 | 72,894 | 11,702 | 27,043 | | December 2025 | 44,195 | 75,884 | 12,792 | 30,460 | | January 2026 | 60,310 | 77,740 | 13,241 | 46,290 | | February 2026 | 51,665 | 74,076 | 12,953 | 37,841 | | March 2026 | 45,281 | 79,021 | 12,907 | 31,619 | ## Corridors and the disclosure rule A corridor-month is published only if it has at least **30 consignments**, from at least **5 different billing customers**, with **no single customer above 50%** of them. This stops any corridor from revealing one company’s shipments. 334 corridor-months were withheld by this rule. A corridor enters the index only if it passes in every month; 15 did, and the largest 12 by tonnes are shown. Corridors are state to state, so a busy corridor may be one large flow or many small ones. ## Limitations - This is SSL’s network, not the whole Indian market. A rise can mean the market grew, or that SSL won more of it. - Charged weight can exceed actual weight (minimum charges and volumetric rules), so tonnes are chargeable tonnes. - Declared goods value is what shippers state on the documents; it is not audited by SSL. - States are taken as written in the register, with spelling variants merged (for example Orissa → Odisha). - Eight months is a short series: no seasonal adjustment is attempted until two full years exist. ## Revision policy The index is rebuilt in full every month from the register, so late entries can revise recent months; earlier months are not frozen. The base month stays August 2025 unless a rebase is announced a month in advance. Every release carries a version tag (current: `2026-03`) in the JSON file, so a citation can name the release it used. ## Reproduce it `python3 scripts/freight-index-build.py` reads the register read-only and writes pooled monthly volumes to `data/freightindex/cells.json` (no names, no prices). `node scripts/freight-index-update.mjs` turns that file into the index, the commentary, the CSV and the JSON, deterministically: the same input always gives the same bytes. Tests: `node --test scripts/freight-index-update.test.mjs`. ## Licence and citation Licensed under [Creative Commons Attribution 4.0 (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/). Reuse freely, including commercially, with this citation: Safe & Secure Logistics (2026). SSL Movement Index, August 2025 to March 2026 (August 2025 = 100). https://safeandsecure.in/movement-index/ · licensed CC BY 4.0. [Download CSV](https://safeandsecure.in/movement-index/movement-index.csv) · [JSON](https://safeandsecure.in/movement-index/data.json) · [Back to the index](https://safeandsecure.in/movement-index/) --- Source: https://safeandsecure.in/movement-index/methodology/ (the HTML page is the record; this markdown twin was generated from it on 2026-11-11). Publisher: Safe & Secure Logistics Private Limited, https://safeandsecure.in/. Figures and their periods: https://safeandsecure.in/facts/